diff --git a/src/main/java/org/openepics/names/old/model/Device.java b/src/main/java/org/openepics/names/old/model/Device.java
index aa2565afb16d7694d9c24c7802d23d01958ee73f..3a0155fb0af97ddf9b0bd5ad4982311f2bd61b88 100644
--- a/src/main/java/org/openepics/names/old/model/Device.java
+++ b/src/main/java/org/openepics/names/old/model/Device.java
@@ -55,8 +55,12 @@ public class Device extends Persistable {
      */
     public UUID getUuid() { return UUID.fromString(uuid); }
 
-    @Override public boolean equals(Object other) {
-        return other instanceof Device && ((Device) other).getUuid().equals(getUuid());
+    @Override
+    public boolean equals(Object other) {
+        if (other instanceof Device object) {
+            return object.getUuid().equals(getUuid());
+        }
+        return false;
     }
 
     @Override
diff --git a/src/main/java/org/openepics/names/old/model/NamePart.java b/src/main/java/org/openepics/names/old/model/NamePart.java
index b80c650b451a86ba393e8f65ffff26033111511f..339ea5ce768adad911c690cc30ce847d3460978a 100644
--- a/src/main/java/org/openepics/names/old/model/NamePart.java
+++ b/src/main/java/org/openepics/names/old/model/NamePart.java
@@ -78,7 +78,10 @@ public class NamePart extends Persistable {
     public NamePartType getNamePartType() { return namePartType; }
 
     @Override public boolean equals(Object other) {
-        return other instanceof NamePart && ((NamePart) other).getUuid().equals(getUuid());
+        if (other instanceof NamePart object) {
+            return object.getUuid().equals(getUuid());
+        }
+        return false;
     }
 
     @Override
diff --git a/src/main/java/org/openepics/names/old/model/UserAccount.java b/src/main/java/org/openepics/names/old/model/UserAccount.java
index 739f460b760396cabbfdf44ebe160923b45210f5..d6b6921b17117c30c450dbfb67851afec223b12d 100644
--- a/src/main/java/org/openepics/names/old/model/UserAccount.java
+++ b/src/main/java/org/openepics/names/old/model/UserAccount.java
@@ -78,7 +78,10 @@ public class UserAccount extends Persistable {
     }
 
     @Override public boolean equals(Object other) {
-        return other instanceof UserAccount && ((UserAccount) other).getUsername().equals(getUsername());
+        if (other instanceof UserAccount object) {
+            return object.getUsername().equals(getUsername());
+        }
+        return false;
     }
 
     @Override public String toString(){
diff --git a/src/main/java/org/openepics/names/repository/DeviceGroupRepository.java b/src/main/java/org/openepics/names/repository/DeviceGroupRepository.java
index 0dc600b44e630294e8fb03bb6f919a8d802f827e..40640ef850a6b241344393d01c35e6f9361740de 100644
--- a/src/main/java/org/openepics/names/repository/DeviceGroupRepository.java
+++ b/src/main/java/org/openepics/names/repository/DeviceGroupRepository.java
@@ -32,6 +32,9 @@ import javax.persistence.criteria.Subquery;
 
 import org.apache.commons.lang3.BooleanUtils;
 import org.openepics.names.repository.model.DeviceGroup;
+import org.openepics.names.repository.model.NameStructure;
+import org.openepics.names.repository.model.Persistable;
+import org.openepics.names.repository.model.Structure;
 import org.openepics.names.rest.beans.FieldStructure;
 import org.openepics.names.rest.beans.Status;
 import org.springframework.stereotype.Repository;
@@ -195,35 +198,35 @@ public class DeviceGroupRepository {
         if (orderBy != null) {
             if (BooleanUtils.toBoolean(isAsc)) {
                 if (FieldStructure.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("name")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_NAME)));
                 } else if (FieldStructure.MNEMONIC.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.MNEMONICEQUIVALENCE.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic_equivalence")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE)));
                 } else if (FieldStructure.MNEMONICPATH.equals(orderBy)) {
-                    cq.orderBy(cb.asc(cb.function("get_mnemonic_path_devicegroup", String.class, from.get("uuid"))));
+                    cq.orderBy(cb.asc(cb.function(DeviceGroup.FUNCTION_GET_MNEMONIC_PATH_DEVICEGROUP, String.class, from.get(NameStructure.FIELD_UUID))));
                 } else if (FieldStructure.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("description")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldStructure.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("requested")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.asc(from.get("convention_name")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_NAME)));
                 }
             } else {
                 if (FieldStructure.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("name")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_NAME)));
                 } else if (FieldStructure.MNEMONIC.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("mnemonic")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.MNEMONICEQUIVALENCE.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("mnemonic_equivalence")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE)));
                 } else if (FieldStructure.MNEMONICPATH.equals(orderBy)) {
-                    cq.orderBy(cb.desc(cb.function("get_mnemonic_path_devicegroup", String.class, from.get("uuid"))));
+                    cq.orderBy(cb.desc(cb.function(DeviceGroup.FUNCTION_GET_MNEMONIC_PATH_DEVICEGROUP, String.class, from.get(NameStructure.FIELD_UUID))));
                 } else if (FieldStructure.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("description")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldStructure.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("requested")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.desc(from.get("name")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_NAME)));
                 }
             }
         }
@@ -282,14 +285,14 @@ public class DeviceGroupRepository {
 
             Root<DeviceGroup> fromSub = sub.from(DeviceGroup.class);
             sub.where(cb.and(
-                    cb.equal(fromSub.get("uuid"),   from.get("uuid")),
-                    cb.equal(fromSub.get("latest"), Boolean.TRUE)
+                    cb.equal(fromSub.get(NameStructure.FIELD_UUID),   from.get(NameStructure.FIELD_UUID)),
+                    cb.equal(fromSub.get(NameStructure.FIELD_LATEST), Boolean.TRUE)
                     ));
-            sub.select(fromSub.get("id"));
+            sub.select(fromSub.get(Persistable.FIELD_ID));
 
             Predicate predicateExcludeInclude =
                     cb.or(
-                            cb.not(cb.lessThan(from.get("id").as(Long.class), sub)),
+                            cb.not(cb.lessThan(from.get(Persistable.FIELD_ID).as(Long.class), sub)),
                             cb.not(cb.exists(sub)));
             predicates.add(predicateExcludeInclude);
         }
@@ -297,12 +300,12 @@ public class DeviceGroupRepository {
         if (statuses != null) {
             List<Predicate> predicatesStatus = new ArrayList<>();
             for (Status status : statuses) {
-                predicatesStatus.add(cb.equal(from.get("status"), status));
+                predicatesStatus.add(cb.equal(from.get(NameStructure.FIELD_STATUS), status));
             }
-            predicates.add(cb.or((Predicate[]) predicatesStatus.toArray(new Predicate[0])));
+            predicates.add(cb.or(predicatesStatus.toArray(new Predicate[0])));
         }
         if (deleted != null) {
-            predicates.add(cb.equal(from.get("deleted"), deleted));
+            predicates.add(cb.equal(from.get(NameStructure.FIELD_DELETED), deleted));
         }
         if (queryFields != null) {
             for (int i=0; i<queryFields.length; i++) {
@@ -325,25 +328,25 @@ public class DeviceGroupRepository {
 
                 switch (queryFields[i]) {
                     case UUID:
-                        predicates.add(cb.and(cb.equal(from.get("uuid"), queryValue)));
+                        predicates.add(cb.and(cb.equal(from.get(NameStructure.FIELD_UUID), queryValue)));
                         break;
                     case PARENT:
-                        predicates.add(cb.and(cb.equal(from.get("parent_uuid"), queryValue)));
+                        predicates.add(cb.and(cb.equal(from.get(DeviceGroup.FIELD_PARENT_UUID), queryValue)));
                         break;
                     case NAME:
-                        predicates.add(cb.and(cb.like(from.get("name"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_NAME), queryValue)));
                         break;
                     case MNEMONIC:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC), queryValue)));
                         break;
                     case MNEMONICEQUIVALENCE:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic_equivalence"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE), queryValue)));
                         break;
                     case MNEMONICPATH:
-                        predicates.add(cb.and(cb.like(cb.function("get_mnemonic_path_devicegroup", String.class, from.get("uuid")), queryValue)));
+                        predicates.add(cb.and(cb.like(cb.function(DeviceGroup.FUNCTION_GET_MNEMONIC_PATH_DEVICEGROUP, String.class, from.get(NameStructure.FIELD_UUID)), queryValue)));
                         break;
                     case DESCRIPTION:
-                        predicates.add(cb.and(cb.like(from.get("description"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(NameStructure.FIELD_DESCRIPTION), queryValue)));
                         break;
                     default:
                         continue;
diff --git a/src/main/java/org/openepics/names/repository/DeviceTypeRepository.java b/src/main/java/org/openepics/names/repository/DeviceTypeRepository.java
index 9f2619fb0ba608cd78e976e63eb4906d3df9da68..1c6449d01e8dc0b26c317dcb8eb5b7acfe194dd8 100644
--- a/src/main/java/org/openepics/names/repository/DeviceTypeRepository.java
+++ b/src/main/java/org/openepics/names/repository/DeviceTypeRepository.java
@@ -32,6 +32,9 @@ import javax.persistence.criteria.Subquery;
 
 import org.apache.commons.lang3.BooleanUtils;
 import org.openepics.names.repository.model.DeviceType;
+import org.openepics.names.repository.model.NameStructure;
+import org.openepics.names.repository.model.Persistable;
+import org.openepics.names.repository.model.Structure;
 import org.openepics.names.rest.beans.FieldStructure;
 import org.openepics.names.rest.beans.Status;
 import org.springframework.stereotype.Repository;
@@ -195,35 +198,35 @@ public class DeviceTypeRepository {
         if (orderBy != null) {
             if (BooleanUtils.toBoolean(isAsc)) {
                 if (FieldStructure.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("name")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_NAME)));
                 } else if (FieldStructure.MNEMONIC.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.MNEMONICEQUIVALENCE.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic_equivalence")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE)));
                 } else if (FieldStructure.MNEMONICPATH.equals(orderBy)) {
-                    cq.orderBy(cb.asc(cb.function("get_mnemonic_path_devicetype", String.class, from.get("uuid"))));
+                    cq.orderBy(cb.asc(cb.function(DeviceType.FUNCTION_GET_MNEMONIC_PATH_DEVICETYPE, String.class, from.get(NameStructure.FIELD_UUID))));
                 } else if (FieldStructure.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("description")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldStructure.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("requested")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.asc(from.get("convention_name")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_NAME)));
                 }
             } else {
                 if (FieldStructure.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("name")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_NAME)));
                 } else if (FieldStructure.MNEMONIC.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("mnemonic")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.MNEMONICEQUIVALENCE.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("mnemonic_equivalence")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE)));
                 } else if (FieldStructure.MNEMONICPATH.equals(orderBy)) {
-                    cq.orderBy(cb.desc(cb.function("get_mnemonic_path_devicetype", String.class, from.get("uuid"))));
+                    cq.orderBy(cb.desc(cb.function(DeviceType.FUNCTION_GET_MNEMONIC_PATH_DEVICETYPE, String.class, from.get(NameStructure.FIELD_UUID))));
                 } else if (FieldStructure.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("description")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldStructure.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("requested")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.desc(from.get("name")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_NAME)));
                 }
             }
         }
@@ -282,14 +285,14 @@ public class DeviceTypeRepository {
 
             Root<DeviceType> fromSub = sub.from(DeviceType.class);
             sub.where(cb.and(
-                    cb.equal(fromSub.get("uuid"),   from.get("uuid")),
-                    cb.equal(fromSub.get("latest"), Boolean.TRUE)
+                    cb.equal(fromSub.get(NameStructure.FIELD_UUID),   from.get(NameStructure.FIELD_UUID)),
+                    cb.equal(fromSub.get(NameStructure.FIELD_LATEST), Boolean.TRUE)
                     ));
-            sub.select(fromSub.get("id"));
+            sub.select(fromSub.get(Persistable.FIELD_ID));
 
             Predicate predicateExcludeInclude =
                     cb.or(
-                            cb.not(cb.lessThan(from.get("id").as(Long.class), sub)),
+                            cb.not(cb.lessThan(from.get(Persistable.FIELD_ID).as(Long.class), sub)),
                             cb.not(cb.exists(sub)));
             predicates.add(predicateExcludeInclude);
         }
@@ -297,12 +300,12 @@ public class DeviceTypeRepository {
         if (statuses != null) {
             List<Predicate> predicatesStatus = new ArrayList<>();
             for (Status status : statuses) {
-                predicatesStatus.add(cb.equal(from.get("status"), status));
+                predicatesStatus.add(cb.equal(from.get(NameStructure.FIELD_STATUS), status));
             }
-            predicates.add(cb.or((Predicate[]) predicatesStatus.toArray(new Predicate[0])));
+            predicates.add(cb.or(predicatesStatus.toArray(new Predicate[0])));
         }
         if (deleted != null) {
-            predicates.add(cb.equal(from.get("deleted"), deleted));
+            predicates.add(cb.equal(from.get(NameStructure.FIELD_DELETED), deleted));
         }
         if (queryFields != null) {
             for (int i=0; i<queryFields.length; i++) {
@@ -325,25 +328,25 @@ public class DeviceTypeRepository {
 
                 switch (queryFields[i]) {
                     case UUID:
-                        predicates.add(cb.and(cb.equal(from.get("uuid"), queryValue)));
+                        predicates.add(cb.and(cb.equal(from.get(NameStructure.FIELD_UUID), queryValue)));
                         break;
                     case PARENT:
-                        predicates.add(cb.and(cb.equal(from.get("parent_uuid"), queryValue)));
+                        predicates.add(cb.and(cb.equal(from.get(DeviceType.FIELD_PARENT_UUID), queryValue)));
                         break;
                     case NAME:
-                        predicates.add(cb.and(cb.like(from.get("name"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_NAME), queryValue)));
                         break;
                     case MNEMONIC:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC), queryValue)));
                         break;
                     case MNEMONICEQUIVALENCE:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic_equivalence"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE), queryValue)));
                         break;
                     case MNEMONICPATH:
-                        predicates.add(cb.and(cb.like(cb.function("get_mnemonic_path_devicetype", String.class, from.get("uuid")), queryValue)));
+                        predicates.add(cb.and(cb.like(cb.function(DeviceType.FUNCTION_GET_MNEMONIC_PATH_DEVICETYPE, String.class, from.get(NameStructure.FIELD_UUID)), queryValue)));
                         break;
                     case DESCRIPTION:
-                        predicates.add(cb.and(cb.like(from.get("description"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(NameStructure.FIELD_DESCRIPTION), queryValue)));
                         break;
                     default:
                         continue;
diff --git a/src/main/java/org/openepics/names/repository/DisciplineRepository.java b/src/main/java/org/openepics/names/repository/DisciplineRepository.java
index 52de025329ac5b0ea544e3b8eb88ec788be513a3..043b888d5c850953fbfd5afaf3f436f86964abbd 100644
--- a/src/main/java/org/openepics/names/repository/DisciplineRepository.java
+++ b/src/main/java/org/openepics/names/repository/DisciplineRepository.java
@@ -32,6 +32,9 @@ import javax.persistence.criteria.Subquery;
 
 import org.apache.commons.lang3.BooleanUtils;
 import org.openepics.names.repository.model.Discipline;
+import org.openepics.names.repository.model.NameStructure;
+import org.openepics.names.repository.model.Persistable;
+import org.openepics.names.repository.model.Structure;
 import org.openepics.names.rest.beans.FieldStructure;
 import org.openepics.names.rest.beans.Status;
 import org.springframework.stereotype.Repository;
@@ -195,35 +198,35 @@ public class DisciplineRepository {
         if (orderBy != null) {
             if (BooleanUtils.toBoolean(isAsc)) {
                 if (FieldStructure.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("name")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_NAME)));
                 } else if (FieldStructure.MNEMONIC.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.MNEMONICEQUIVALENCE.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic_equivalence")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE)));
                 } else if (FieldStructure.MNEMONICPATH.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("description")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldStructure.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("requested")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.asc(from.get("convention_name")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_NAME)));
                 }
             } else {
                 if (FieldStructure.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("name")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_NAME)));
                 } else if (FieldStructure.MNEMONIC.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("mnemonic")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.MNEMONICEQUIVALENCE.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("mnemonic_equivalence")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE)));
                 } else if (FieldStructure.MNEMONICPATH.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("description")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldStructure.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("requested")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.desc(from.get("name")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_NAME)));
                 }
             }
         }
@@ -282,14 +285,14 @@ public class DisciplineRepository {
 
             Root<Discipline> fromSub = sub.from(Discipline.class);
             sub.where(cb.and(
-                    cb.equal(fromSub.get("uuid"),   from.get("uuid")),
-                    cb.equal(fromSub.get("latest"), Boolean.TRUE)
+                    cb.equal(fromSub.get(NameStructure.FIELD_UUID),   from.get(NameStructure.FIELD_UUID)),
+                    cb.equal(fromSub.get(NameStructure.FIELD_LATEST), Boolean.TRUE)
                     ));
-            sub.select(fromSub.get("id"));
+            sub.select(fromSub.get(Persistable.FIELD_ID));
 
             Predicate predicateExcludeInclude =
                     cb.or(
-                            cb.not(cb.lessThan(from.get("id").as(Long.class), sub)),
+                            cb.not(cb.lessThan(from.get(Persistable.FIELD_ID).as(Long.class), sub)),
                             cb.not(cb.exists(sub)));
             predicates.add(predicateExcludeInclude);
         }
@@ -297,12 +300,12 @@ public class DisciplineRepository {
         if (statuses != null) {
             List<Predicate> predicatesStatus = new ArrayList<>();
             for (Status status : statuses) {
-                predicatesStatus.add(cb.equal(from.get("status"), status));
+                predicatesStatus.add(cb.equal(from.get(NameStructure.FIELD_STATUS), status));
             }
-            predicates.add(cb.or((Predicate[]) predicatesStatus.toArray(new Predicate[0])));
+            predicates.add(cb.or(predicatesStatus.toArray(new Predicate[0])));
         }
         if (deleted != null) {
-            predicates.add(cb.equal(from.get("deleted"), deleted));
+            predicates.add(cb.equal(from.get(NameStructure.FIELD_DELETED), deleted));
         }
         if (queryFields != null) {
             for (int i=0; i<queryFields.length; i++) {
@@ -325,22 +328,22 @@ public class DisciplineRepository {
 
                 switch (queryFields[i]) {
                     case UUID:
-                        predicates.add(cb.and(cb.equal(from.get("uuid"), queryValue)));
+                        predicates.add(cb.and(cb.equal(from.get(NameStructure.FIELD_UUID), queryValue)));
                         break;
                     case NAME:
-                        predicates.add(cb.and(cb.like(from.get("name"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_NAME), queryValue)));
                         break;
                     case MNEMONIC:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC), queryValue)));
                         break;
                     case MNEMONICEQUIVALENCE:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic_equivalence"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE), queryValue)));
                         break;
                     case MNEMONICPATH:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC), queryValue)));
                         break;
                     case DESCRIPTION:
-                        predicates.add(cb.and(cb.like(from.get("description"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(NameStructure.FIELD_DESCRIPTION), queryValue)));
                         break;
                     default:
                         continue;
diff --git a/src/main/java/org/openepics/names/repository/NameRepository.java b/src/main/java/org/openepics/names/repository/NameRepository.java
index d31a74f5b11424fdcd1ed93ef165612b9b20496a..4db17939ef6a0deb7cd9efaf4ef5a1d0bca3d988 100644
--- a/src/main/java/org/openepics/names/repository/NameRepository.java
+++ b/src/main/java/org/openepics/names/repository/NameRepository.java
@@ -31,6 +31,7 @@ import javax.persistence.criteria.Root;
 
 import org.apache.commons.lang3.BooleanUtils;
 import org.openepics.names.repository.model.Name;
+import org.openepics.names.repository.model.NameStructure;
 import org.openepics.names.rest.beans.FieldName;
 import org.springframework.stereotype.Repository;
 
@@ -164,35 +165,35 @@ public class NameRepository {
         if (orderBy != null) {
             if (BooleanUtils.toBoolean(isAsc)) {
                 if (FieldName.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("convention_name")));
+                    cq.orderBy(cb.asc(from.get(Name.FIELD_CONVENTION_NAME)));
                 } else if (FieldName.NAMEEQUIVALENCE.equals(orderBy)) {
-                        cq.orderBy(cb.asc(from.get("convention_name_equivalence")));
+                        cq.orderBy(cb.asc(from.get(Name.FIELD_CONVENTION_NAME_EQUIVALENCE)));
                 } else if (FieldName.SYSTEMSTRUCTURE.equals(orderBy)) {
-                    cq.orderBy(cb.asc(cb.function("get_mnemonic_path_system_structure", String.class, from.get("convention_name"))));
+                    cq.orderBy(cb.asc(cb.function(NameStructure.FUNCTION_GET_MNEMONIC_PATH_SYSTEM_STRUCTURE, String.class, from.get(Name.FIELD_CONVENTION_NAME))));
                 } else if (FieldName.DEVICESTRUCTURE.equals(orderBy)) {
-                    cq.orderBy(cb.asc(cb.function("get_mnemonic_path_device_structure", String.class, from.get("convention_name"))));
+                    cq.orderBy(cb.asc(cb.function(NameStructure.FUNCTION_GET_MNEMONIC_PATH_DEVICE_STRUCTURE, String.class, from.get(Name.FIELD_CONVENTION_NAME))));
                 } else if (FieldName.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("description")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldName.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("requested")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.asc(from.get("convention_name")));
+                    cq.orderBy(cb.asc(from.get(Name.FIELD_CONVENTION_NAME)));
                 }
             } else {
                 if (FieldName.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("convention_name")));
+                    cq.orderBy(cb.desc(from.get(Name.FIELD_CONVENTION_NAME)));
                 } else if (FieldName.NAMEEQUIVALENCE.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("convention_name_equivalence")));
+                    cq.orderBy(cb.desc(from.get(Name.FIELD_CONVENTION_NAME_EQUIVALENCE)));
                 } else if (FieldName.SYSTEMSTRUCTURE.equals(orderBy)) {
-                    cq.orderBy(cb.desc(cb.function("get_mnemonic_path_system_structure", String.class, from.get("convention_name"))));
+                    cq.orderBy(cb.desc(cb.function(NameStructure.FUNCTION_GET_MNEMONIC_PATH_SYSTEM_STRUCTURE, String.class, from.get(Name.FIELD_CONVENTION_NAME))));
                 } else if (FieldName.DEVICESTRUCTURE.equals(orderBy)) {
-                    cq.orderBy(cb.desc(cb.function("get_mnemonic_path_device_structure", String.class, from.get("convention_name"))));
+                    cq.orderBy(cb.desc(cb.function(NameStructure.FUNCTION_GET_MNEMONIC_PATH_DEVICE_STRUCTURE, String.class, from.get(Name.FIELD_CONVENTION_NAME))));
                 } else if (FieldName.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("description")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldName.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("requested")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.desc(from.get("convention_name")));
+                    cq.orderBy(cb.desc(from.get(Name.FIELD_CONVENTION_NAME)));
                 }
             }
         }
@@ -233,13 +234,13 @@ public class NameRepository {
             //     select * from Name n where
             //         not(n.latest = false)
 
-            Predicate predicateNotLatest = cb.equal(from.get("latest"), Boolean.FALSE);
+            Predicate predicateNotLatest = cb.equal(from.get(NameStructure.FIELD_LATEST), Boolean.FALSE);
             Predicate predicateExclude   = cb.not(cb.and(predicateNotLatest));
             predicates.add(predicateExclude);
         }
 
         if (deleted != null) {
-            predicates.add(cb.equal(from.get("deleted"), deleted));
+            predicates.add(cb.equal(from.get(NameStructure.FIELD_DELETED), deleted));
         }
         if (queryFields != null) {
             for (int i=0; i<queryFields.length; i++) {
@@ -262,22 +263,22 @@ public class NameRepository {
 
                 switch (queryFields[i]) {
                     case UUID:
-                        predicates.add(cb.and(cb.equal(from.get("uuid"), queryValue)));
+                        predicates.add(cb.and(cb.equal(from.get(NameStructure.FIELD_UUID), queryValue)));
                         break;
                     case NAME:
-                        predicates.add(cb.and(cb.like(from.get("convention_name"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Name.FIELD_CONVENTION_NAME), queryValue)));
                         break;
                     case NAMEEQUIVALENCE:
-                        predicates.add(cb.and(cb.like(from.get("convention_name_equivalence"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Name.FIELD_CONVENTION_NAME_EQUIVALENCE), queryValue)));
                         break;
                     case SYSTEMSTRUCTURE:
-                        predicates.add(cb.and(cb.like(cb.function("get_mnemonic_path_system_structure", String.class, from.get("convention_name")), queryValue)));
+                        predicates.add(cb.and(cb.like(cb.function(NameStructure.FUNCTION_GET_MNEMONIC_PATH_SYSTEM_STRUCTURE, String.class, from.get(Name.FIELD_CONVENTION_NAME)), queryValue)));
                         break;
                     case DEVICESTRUCTURE:
-                        predicates.add(cb.and(cb.like(cb.function("get_mnemonic_path_device_structure", String.class, from.get("convention_name")), queryValue)));
+                        predicates.add(cb.and(cb.like(cb.function(NameStructure.FUNCTION_GET_MNEMONIC_PATH_DEVICE_STRUCTURE, String.class, from.get(Name.FIELD_CONVENTION_NAME)), queryValue)));
                         break;
                     case DESCRIPTION:
-                        predicates.add(cb.and(cb.like(from.get("description"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(NameStructure.FIELD_DESCRIPTION), queryValue)));
                         break;
                     default:
                         continue;
diff --git a/src/main/java/org/openepics/names/repository/SubsystemRepository.java b/src/main/java/org/openepics/names/repository/SubsystemRepository.java
index 1a363fc7c1f664094e166df14043821fc06a450d..0cd577f3400f310bca9960020d3ba0e7689eb062 100644
--- a/src/main/java/org/openepics/names/repository/SubsystemRepository.java
+++ b/src/main/java/org/openepics/names/repository/SubsystemRepository.java
@@ -31,6 +31,9 @@ import javax.persistence.criteria.Root;
 import javax.persistence.criteria.Subquery;
 
 import org.apache.commons.lang3.BooleanUtils;
+import org.openepics.names.repository.model.NameStructure;
+import org.openepics.names.repository.model.Persistable;
+import org.openepics.names.repository.model.Structure;
 import org.openepics.names.repository.model.Subsystem;
 import org.openepics.names.rest.beans.FieldStructure;
 import org.openepics.names.rest.beans.Status;
@@ -195,35 +198,35 @@ public class SubsystemRepository {
         if (orderBy != null) {
             if (BooleanUtils.toBoolean(isAsc)) {
                 if (FieldStructure.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("name")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_NAME)));
                 } else if (FieldStructure.MNEMONIC.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.MNEMONICEQUIVALENCE.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic_equivalence")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE)));
                 } else if (FieldStructure.MNEMONICPATH.equals(orderBy)) {
-                    cq.orderBy(cb.asc(cb.function("get_mnemonic_path_subsystem", String.class, from.get("uuid"))));
+                    cq.orderBy(cb.asc(cb.function(Subsystem.FUNCTION_GET_MNEMONIC_PATH_SUBSYSTEM, String.class, from.get(NameStructure.FIELD_UUID))));
                 } else if (FieldStructure.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("description")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldStructure.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("requested")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.asc(from.get("convention_name")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_NAME)));
                 }
             } else {
                 if (FieldStructure.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("name")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_NAME)));
                 } else if (FieldStructure.MNEMONIC.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("mnemonic")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.MNEMONICEQUIVALENCE.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("mnemonic_equivalence")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE)));
                 } else if (FieldStructure.MNEMONICPATH.equals(orderBy)) {
-                    cq.orderBy(cb.desc(cb.function("get_mnemonic_path_subsystem", String.class, from.get("uuid"))));
+                    cq.orderBy(cb.desc(cb.function(Subsystem.FUNCTION_GET_MNEMONIC_PATH_SUBSYSTEM, String.class, from.get(NameStructure.FIELD_UUID))));
                 } else if (FieldStructure.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("description")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldStructure.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("requested")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.desc(from.get("name")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_NAME)));
                 }
             }
         }
@@ -282,14 +285,14 @@ public class SubsystemRepository {
 
             Root<Subsystem> fromSub = sub.from(Subsystem.class);
             sub.where(cb.and(
-                    cb.equal(fromSub.get("uuid"),   from.get("uuid")),
-                    cb.equal(fromSub.get("latest"), Boolean.TRUE)
+                    cb.equal(fromSub.get(NameStructure.FIELD_UUID),   from.get(NameStructure.FIELD_UUID)),
+                    cb.equal(fromSub.get(NameStructure.FIELD_LATEST), Boolean.TRUE)
                     ));
-            sub.select(fromSub.get("id"));
+            sub.select(fromSub.get(Persistable.FIELD_ID));
 
             Predicate predicateExcludeInclude =
                     cb.or(
-                            cb.not(cb.lessThan(from.get("id").as(Long.class), sub)),
+                            cb.not(cb.lessThan(from.get(Persistable.FIELD_ID).as(Long.class), sub)),
                             cb.not(cb.exists(sub)));
             predicates.add(predicateExcludeInclude);
         }
@@ -297,12 +300,12 @@ public class SubsystemRepository {
         if (statuses != null) {
             List<Predicate> predicatesStatus = new ArrayList<>();
             for (Status status : statuses) {
-                predicatesStatus.add(cb.equal(from.get("status"), status));
+                predicatesStatus.add(cb.equal(from.get(NameStructure.FIELD_STATUS), status));
             }
-            predicates.add(cb.or((Predicate[]) predicatesStatus.toArray(new Predicate[0])));
+            predicates.add(cb.or(predicatesStatus.toArray(new Predicate[0])));
         }
         if (deleted != null) {
-            predicates.add(cb.equal(from.get("deleted"), deleted));
+            predicates.add(cb.equal(from.get(NameStructure.FIELD_DELETED), deleted));
         }
         if (queryFields != null) {
             for (int i=0; i<queryFields.length; i++) {
@@ -325,25 +328,25 @@ public class SubsystemRepository {
 
                 switch (queryFields[i]) {
                     case UUID:
-                        predicates.add(cb.and(cb.equal(from.get("uuid"), queryValue)));
+                        predicates.add(cb.and(cb.equal(from.get(NameStructure.FIELD_UUID), queryValue)));
                         break;
                     case PARENT:
-                        predicates.add(cb.and(cb.equal(from.get("parent_uuid"), queryValue)));
+                        predicates.add(cb.and(cb.equal(from.get(Subsystem.FIELD_PARENT_UUID), queryValue)));
                         break;
                     case NAME:
-                        predicates.add(cb.and(cb.like(from.get("name"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_NAME), queryValue)));
                         break;
                     case MNEMONIC:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC), queryValue)));
                         break;
                     case MNEMONICEQUIVALENCE:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic_equivalence"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE), queryValue)));
                         break;
                     case MNEMONICPATH:
-                        predicates.add(cb.and(cb.like(cb.function("get_mnemonic_path_subsystem", String.class, from.get("uuid")), queryValue)));
+                        predicates.add(cb.and(cb.like(cb.function(Subsystem.FUNCTION_GET_MNEMONIC_PATH_SUBSYSTEM, String.class, from.get(NameStructure.FIELD_UUID)), queryValue)));
                         break;
                     case DESCRIPTION:
-                        predicates.add(cb.and(cb.like(from.get("description"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(NameStructure.FIELD_DESCRIPTION), queryValue)));
                         break;
                     default:
                         continue;
diff --git a/src/main/java/org/openepics/names/repository/SystemGroupRepository.java b/src/main/java/org/openepics/names/repository/SystemGroupRepository.java
index 7f7f5c607d1cd7782303430c8af04fc022e50eff..23945f0598080eeac55af0ce0d5092b799991645 100644
--- a/src/main/java/org/openepics/names/repository/SystemGroupRepository.java
+++ b/src/main/java/org/openepics/names/repository/SystemGroupRepository.java
@@ -31,6 +31,9 @@ import javax.persistence.criteria.Root;
 import javax.persistence.criteria.Subquery;
 
 import org.apache.commons.lang3.BooleanUtils;
+import org.openepics.names.repository.model.NameStructure;
+import org.openepics.names.repository.model.Persistable;
+import org.openepics.names.repository.model.Structure;
 import org.openepics.names.repository.model.SystemGroup;
 import org.openepics.names.rest.beans.FieldStructure;
 import org.openepics.names.rest.beans.Status;
@@ -191,35 +194,35 @@ public class SystemGroupRepository {
         if (orderBy != null) {
             if (BooleanUtils.toBoolean(isAsc)) {
                 if (FieldStructure.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("name")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_NAME)));
                 } else if (FieldStructure.MNEMONIC.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.MNEMONICEQUIVALENCE.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic_equivalence")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE)));
                 } else if (FieldStructure.MNEMONICPATH.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("description")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldStructure.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("requested")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.asc(from.get("convention_name")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_NAME)));
                 }
             } else {
                 if (FieldStructure.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("name")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_NAME)));
                 } else if (FieldStructure.MNEMONIC.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("mnemonic")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.MNEMONICEQUIVALENCE.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("mnemonic_equivalence")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE)));
                 } else if (FieldStructure.MNEMONICPATH.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("mnemonic")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("description")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldStructure.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("requested")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.desc(from.get("name")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_NAME)));
                 }
             }
         }
@@ -278,14 +281,14 @@ public class SystemGroupRepository {
 
             Root<SystemGroup> fromSub = sub.from(SystemGroup.class);
             sub.where(cb.and(
-                    cb.equal(fromSub.get("uuid"),   from.get("uuid")),
-                    cb.equal(fromSub.get("latest"), Boolean.TRUE)
+                    cb.equal(fromSub.get(NameStructure.FIELD_UUID),   from.get(NameStructure.FIELD_UUID)),
+                    cb.equal(fromSub.get(NameStructure.FIELD_LATEST), Boolean.TRUE)
                     ));
-            sub.select(fromSub.get("id"));
+            sub.select(fromSub.get(Persistable.FIELD_ID));
 
             Predicate predicateExcludeInclude =
                     cb.or(
-                            cb.not(cb.lessThan(from.get("id").as(Long.class), sub)),
+                            cb.not(cb.lessThan(from.get(Persistable.FIELD_ID).as(Long.class), sub)),
                             cb.not(cb.exists(sub)));
             predicates.add(predicateExcludeInclude);
         }
@@ -293,12 +296,12 @@ public class SystemGroupRepository {
         if (statuses != null) {
             List<Predicate> predicatesStatus = new ArrayList<>();
             for (Status status : statuses) {
-                predicatesStatus.add(cb.equal(from.get("status"), status));
+                predicatesStatus.add(cb.equal(from.get(NameStructure.FIELD_STATUS), status));
             }
-            predicates.add(cb.or((Predicate[]) predicatesStatus.toArray(new Predicate[0])));
+            predicates.add(cb.or(predicatesStatus.toArray(new Predicate[0])));
         }
         if (deleted != null) {
-            predicates.add(cb.equal(from.get("deleted"), deleted));
+            predicates.add(cb.equal(from.get(NameStructure.FIELD_DELETED), deleted));
         }
         if (queryFields != null) {
             for (int i=0; i<queryFields.length; i++) {
@@ -321,22 +324,22 @@ public class SystemGroupRepository {
 
                 switch (queryFields[i]) {
                     case UUID:
-                        predicates.add(cb.and(cb.equal(from.get("uuid"), queryValue)));
+                        predicates.add(cb.and(cb.equal(from.get(NameStructure.FIELD_UUID), queryValue)));
                         break;
                     case NAME:
-                        predicates.add(cb.and(cb.like(from.get("name"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_NAME), queryValue)));
                         break;
                     case MNEMONIC:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC), queryValue)));
                         break;
                     case MNEMONICEQUIVALENCE:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic_equivalence"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE), queryValue)));
                         break;
                     case MNEMONICPATH:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC), queryValue)));
                         break;
                     case DESCRIPTION:
-                        predicates.add(cb.and(cb.like(from.get("description"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(NameStructure.FIELD_DESCRIPTION), queryValue)));
                         break;
                     default:
                         continue;
diff --git a/src/main/java/org/openepics/names/repository/SystemRepository.java b/src/main/java/org/openepics/names/repository/SystemRepository.java
index beead5c67a09d0773209ef8b9f0ded0dea0ea1a7..b265a490169acde8716446f62f4f5605cfbed89d 100644
--- a/src/main/java/org/openepics/names/repository/SystemRepository.java
+++ b/src/main/java/org/openepics/names/repository/SystemRepository.java
@@ -31,6 +31,9 @@ import javax.persistence.criteria.Root;
 import javax.persistence.criteria.Subquery;
 
 import org.apache.commons.lang3.BooleanUtils;
+import org.openepics.names.repository.model.NameStructure;
+import org.openepics.names.repository.model.Persistable;
+import org.openepics.names.repository.model.Structure;
 import org.openepics.names.repository.model.System;
 import org.openepics.names.rest.beans.FieldStructure;
 import org.openepics.names.rest.beans.Status;
@@ -195,35 +198,35 @@ public class SystemRepository {
         if (orderBy != null) {
             if (BooleanUtils.toBoolean(isAsc)) {
                 if (FieldStructure.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("name")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_NAME)));
                 } else if (FieldStructure.MNEMONIC.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.MNEMONICEQUIVALENCE.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("mnemonic_equivalence")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE)));
                 } else if (FieldStructure.MNEMONICPATH.equals(orderBy)) {
-                    cq.orderBy(cb.asc(cb.function("get_mnemonic_path_system", String.class, from.get("uuid"))));
+                    cq.orderBy(cb.asc(cb.function(System.FUNCTION_GET_MNEMONIC_PATH_SYSTEM, String.class, from.get(NameStructure.FIELD_UUID))));
                 } else if (FieldStructure.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("description")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldStructure.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.asc(from.get("requested")));
+                    cq.orderBy(cb.asc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.asc(from.get("convention_name")));
+                    cq.orderBy(cb.asc(from.get(Structure.FIELD_NAME)));
                 }
             } else {
                 if (FieldStructure.NAME.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("name")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_NAME)));
                 } else if (FieldStructure.MNEMONIC.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("mnemonic")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_MNEMONIC)));
                 } else if (FieldStructure.MNEMONICEQUIVALENCE.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("mnemonic_equivalence")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE)));
                 } else if (FieldStructure.MNEMONICPATH.equals(orderBy)) {
-                    cq.orderBy(cb.desc(cb.function("get_mnemonic_path_system", String.class, from.get("uuid"))));
+                    cq.orderBy(cb.desc(cb.function(System.FUNCTION_GET_MNEMONIC_PATH_SYSTEM, String.class, from.get(NameStructure.FIELD_UUID))));
                 } else if (FieldStructure.DESCRIPTION.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("description")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_DESCRIPTION)));
                 } else if (FieldStructure.WHEN.equals(orderBy)) {
-                    cq.orderBy(cb.desc(from.get("requested")));
+                    cq.orderBy(cb.desc(from.get(NameStructure.FIELD_REQUESTED)));
                 } else {
-                    cq.orderBy(cb.desc(from.get("name")));
+                    cq.orderBy(cb.desc(from.get(Structure.FIELD_NAME)));
                 }
             }
         }
@@ -282,14 +285,14 @@ public class SystemRepository {
 
             Root<System> fromSub = sub.from(System.class);
             sub.where(cb.and(
-                    cb.equal(fromSub.get("uuid"),   from.get("uuid")),
-                    cb.equal(fromSub.get("latest"), Boolean.TRUE)
+                    cb.equal(fromSub.get(NameStructure.FIELD_UUID),   from.get(NameStructure.FIELD_UUID)),
+                    cb.equal(fromSub.get(NameStructure.FIELD_LATEST), Boolean.TRUE)
                     ));
-            sub.select(fromSub.get("id"));
+            sub.select(fromSub.get(Persistable.FIELD_ID));
 
             Predicate predicateExcludeInclude =
                     cb.or(
-                            cb.not(cb.lessThan(from.get("id").as(Long.class), sub)),
+                            cb.not(cb.lessThan(from.get(Persistable.FIELD_ID).as(Long.class), sub)),
                             cb.not(cb.exists(sub)));
             predicates.add(predicateExcludeInclude);
         }
@@ -297,12 +300,12 @@ public class SystemRepository {
         if (statuses != null) {
             List<Predicate> predicatesStatus = new ArrayList<>();
             for (Status status : statuses) {
-                predicatesStatus.add(cb.equal(from.get("status"), status));
+                predicatesStatus.add(cb.equal(from.get(NameStructure.FIELD_STATUS), status));
             }
-            predicates.add(cb.or((Predicate[]) predicatesStatus.toArray(new Predicate[0])));
+            predicates.add(cb.or(predicatesStatus.toArray(new Predicate[0])));
         }
         if (deleted != null) {
-            predicates.add(cb.equal(from.get("deleted"), deleted));
+            predicates.add(cb.equal(from.get(NameStructure.FIELD_DELETED), deleted));
         }
         if (queryFields != null) {
             for (int i=0; i<queryFields.length; i++) {
@@ -325,25 +328,25 @@ public class SystemRepository {
 
                 switch (queryFields[i]) {
                     case UUID:
-                        predicates.add(cb.and(cb.equal(from.get("uuid"), queryValue)));
+                        predicates.add(cb.and(cb.equal(from.get(NameStructure.FIELD_UUID), queryValue)));
                         break;
                     case PARENT:
-                        predicates.add(cb.and(cb.equal(from.get("parent_uuid"), queryValue)));
+                        predicates.add(cb.and(cb.equal(from.get(System.FIELD_PARENT_UUID), queryValue)));
                         break;
                     case NAME:
-                        predicates.add(cb.and(cb.like(from.get("name"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_NAME), queryValue)));
                         break;
                     case MNEMONIC:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC), queryValue)));
                         break;
                     case MNEMONICEQUIVALENCE:
-                        predicates.add(cb.and(cb.like(from.get("mnemonic_equivalence"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(Structure.FIELD_MNEMONIC_EQUIVALENCE), queryValue)));
                         break;
                     case MNEMONICPATH:
-                        predicates.add(cb.and(cb.like(cb.function("get_mnemonic_path_system", String.class, from.get("uuid")), queryValue)));
+                        predicates.add(cb.and(cb.like(cb.function(System.FUNCTION_GET_MNEMONIC_PATH_SYSTEM, String.class, from.get(NameStructure.FIELD_UUID)), queryValue)));
                         break;
                     case DESCRIPTION:
-                        predicates.add(cb.and(cb.like(from.get("description"), queryValue)));
+                        predicates.add(cb.and(cb.like(from.get(NameStructure.FIELD_DESCRIPTION), queryValue)));
                         break;
                     default:
                         continue;
diff --git a/src/main/java/org/openepics/names/repository/model/DeviceGroup.java b/src/main/java/org/openepics/names/repository/model/DeviceGroup.java
index 6af57d0f0d31849470671d09d3c6e58dfa917b81..c471df7d143c92218d5dfa08e675874f8210cd6b 100644
--- a/src/main/java/org/openepics/names/repository/model/DeviceGroup.java
+++ b/src/main/java/org/openepics/names/repository/model/DeviceGroup.java
@@ -37,6 +37,10 @@ public class DeviceGroup extends Structure {
      */
     private static final long serialVersionUID = -8762287473417706804L;
 
+    public static final String FIELD_PARENT_UUID = "parent_uuid";
+
+    public static final String FUNCTION_GET_MNEMONIC_PATH_DEVICEGROUP = "get_mnemonic_path_devicegroup";
+
     private String parent_uuid;
 
     public UUID getParentUuid() {
@@ -75,8 +79,12 @@ public class DeviceGroup extends Structure {
         return true;
     }
 
+    @Override
     public boolean equalsId(Object other) {
-        return other instanceof DeviceGroup && ((DeviceGroup) other).getId().equals(getId());
+        if (other instanceof DeviceGroup object) {
+            return object.getId().equals(getId());
+        }
+        return false;
     }
 
     @Override
diff --git a/src/main/java/org/openepics/names/repository/model/DeviceType.java b/src/main/java/org/openepics/names/repository/model/DeviceType.java
index 74696b6cc87f053d73755a69781d2f9bbb851410..065e64f6ed502049435e98b1a767d7be2ef42960 100644
--- a/src/main/java/org/openepics/names/repository/model/DeviceType.java
+++ b/src/main/java/org/openepics/names/repository/model/DeviceType.java
@@ -37,6 +37,10 @@ public class DeviceType extends Structure {
      */
     private static final long serialVersionUID = 2061731870402041740L;
 
+    public static final String FIELD_PARENT_UUID = "parent_uuid";
+
+    public static final String FUNCTION_GET_MNEMONIC_PATH_DEVICETYPE = "get_mnemonic_path_devicetype";
+
     private String parent_uuid;
 
     public UUID getParentUuid() {
@@ -75,8 +79,12 @@ public class DeviceType extends Structure {
         return true;
     }
 
+    @Override
     public boolean equalsId(Object other) {
-        return other instanceof DeviceType && ((DeviceType) other).getId().equals(getId());
+        if (other instanceof DeviceType object) {
+            return object.getId().equals(getId());
+        }
+        return false;
     }
 
     @Override
diff --git a/src/main/java/org/openepics/names/repository/model/Discipline.java b/src/main/java/org/openepics/names/repository/model/Discipline.java
index 6f98141f9dbe6def55ecc3b954dcfb9d221df2a5..24198d4df7f41cc92a0aaa37ec971fc536489f75 100644
--- a/src/main/java/org/openepics/names/repository/model/Discipline.java
+++ b/src/main/java/org/openepics/names/repository/model/Discipline.java
@@ -58,8 +58,12 @@ public class Discipline extends Structure {
         return true;
     }
 
+    @Override
     public boolean equalsId(Object other) {
-        return other instanceof Discipline && ((Discipline) other).getId().equals(getId());
+        if (other instanceof Discipline object) {
+            return object.getId().equals(getId());
+        }
+        return false;
     }
 
     @Override
diff --git a/src/main/java/org/openepics/names/repository/model/Name.java b/src/main/java/org/openepics/names/repository/model/Name.java
index 749b18534efc93036b69008d3fdba5dd8c97f9de..4454e39d87592cb91fb59eae1c4d981f39d7c333 100644
--- a/src/main/java/org/openepics/names/repository/model/Name.java
+++ b/src/main/java/org/openepics/names/repository/model/Name.java
@@ -38,6 +38,14 @@ public class Name extends NameStructure implements Serializable {
      */
     private static final long serialVersionUID = 7313392211143183879L;
 
+    public static final String FIELD_SYSTEM_GROUP_UUID           = "systemgroup_uuid";
+    public static final String FIELD_SYSTEM_UUID                 = "system_uuid";
+    public static final String FIELD_SUBSYSTEM_UUID              = "subsystem_uuid";
+    public static final String FIELD_DEVICETYPE_UUID             = "devicetype_uuid";
+    public static final String FIELD_INSTANCE_INDEX              = "instance_index";
+    public static final String FIELD_CONVENTION_NAME             = "convention_name";
+    public static final String FIELD_CONVENTION_NAME_EQUIVALENCE = "convention_name_equivalence";
+
     private String systemgroup_uuid;
     private String system_uuid;
     private String subsystem_uuid;
@@ -148,8 +156,12 @@ public class Name extends NameStructure implements Serializable {
         return true;
     }
 
+    @Override
     public boolean equalsId(Object other) {
-        return other instanceof Name && ((Name) other).getId().equals(getId());
+        if (other instanceof Name object) {
+            return object.getId().equals(getId());
+        }
+        return false;
     }
 
     @Override
diff --git a/src/main/java/org/openepics/names/repository/model/NameStructure.java b/src/main/java/org/openepics/names/repository/model/NameStructure.java
index 88bd777a07e4a166c2b938792fd3ecc70034c58d..5ef3a2b585bf9a49fce48463bfdf48591182ed29 100644
--- a/src/main/java/org/openepics/names/repository/model/NameStructure.java
+++ b/src/main/java/org/openepics/names/repository/model/NameStructure.java
@@ -43,6 +43,21 @@ public class NameStructure extends Persistable implements Serializable {
      */
     private static final long serialVersionUID = 736094142259082938L;
 
+    public static final String FIELD_UUID              = "uuid";
+    public static final String FIELD_DESCRIPTION       = "description";
+    public static final String FIELD_STATUS            = "status";
+    public static final String FIELD_LATEST            = "latest";
+    public static final String FIELD_DELETED           = "deleted";
+    public static final String FIELD_REQUESTED         = "requested";
+    public static final String FIELD_REQUESTED_BY      = "requested_by";
+    public static final String FIELD_REQUESTED_COMMENT = "requested_comment";
+    public static final String FIELD_PROCESSED         = "processed";
+    public static final String FIELD_PROCESSED_BY      = "processed_by";
+    public static final String FIELD_PROCESSED_COMMENT = "processed_comment";
+
+    public static final String FUNCTION_GET_MNEMONIC_PATH_DEVICE_STRUCTURE = "get_mnemonic_path_device_structure";
+    public static final String FUNCTION_GET_MNEMONIC_PATH_SYSTEM_STRUCTURE = "get_mnemonic_path_system_structure";
+
     private String uuid;
     private String description;
     @Enumerated(EnumType.STRING)
@@ -203,7 +218,10 @@ public class NameStructure extends Persistable implements Serializable {
     }
 
     public boolean equalsId(Object other) {
-        return other instanceof NameStructure && ((NameStructure) other).getId().equals(getId());
+        if (other instanceof NameStructure object) {
+            return object.getId().equals(getId());
+        }
+        return false;
     }
 
     @Override
diff --git a/src/main/java/org/openepics/names/repository/model/Persistable.java b/src/main/java/org/openepics/names/repository/model/Persistable.java
index 4c2370cd308f08688aaf88d17fdd47094f6af3a0..99f23e636d2c6d735e0af861353ba4d574ace0f2 100644
--- a/src/main/java/org/openepics/names/repository/model/Persistable.java
+++ b/src/main/java/org/openepics/names/repository/model/Persistable.java
@@ -33,6 +33,9 @@ public class Persistable implements Serializable {
 
     private static final long serialVersionUID = 8393161299438204843L;
 
+    public static final String FIELD_ID      = "id";
+    public static final String FIELD_VERSION = "version";
+
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
     protected @Nullable Long id;
diff --git a/src/main/java/org/openepics/names/repository/model/Structure.java b/src/main/java/org/openepics/names/repository/model/Structure.java
index 6f526543a79d1b0208cb2dfec414ec447e0a6a93..215eb2770826d19bbcd332b6ae52afc33030f2c4 100644
--- a/src/main/java/org/openepics/names/repository/model/Structure.java
+++ b/src/main/java/org/openepics/names/repository/model/Structure.java
@@ -36,6 +36,10 @@ public class Structure extends NameStructure implements Serializable {
      */
     private static final long serialVersionUID = -5980090194197159918L;
 
+    public static final String FIELD_NAME                 = "name";
+    public static final String FIELD_MNEMONIC             = "mnemonic";
+    public static final String FIELD_MNEMONIC_EQUIVALENCE = "mnemonic_equivalence";
+
     private String name;
     private String mnemonic;
     private String mnemonic_equivalence;
@@ -98,8 +102,12 @@ public class Structure extends NameStructure implements Serializable {
         return true;
     }
 
+    @Override
     public boolean equalsId(Object other) {
-        return other instanceof Structure && ((Structure) other).getId().equals(getId());
+        if (other instanceof Structure object) {
+            return object.getId().equals(getId());
+        }
+        return false;
     }
 
 }
diff --git a/src/main/java/org/openepics/names/repository/model/Subsystem.java b/src/main/java/org/openepics/names/repository/model/Subsystem.java
index 249c9ac3709f59c45a6b96bb20a1eccba6dc344b..f6bd8c9ee72d89cb3e869f82fe22063bea9c2942 100644
--- a/src/main/java/org/openepics/names/repository/model/Subsystem.java
+++ b/src/main/java/org/openepics/names/repository/model/Subsystem.java
@@ -37,6 +37,10 @@ public class Subsystem extends Structure {
      */
     private static final long serialVersionUID = 5662135540008222500L;
 
+    public static final String FIELD_PARENT_UUID = "parent_uuid";
+
+    public static final String FUNCTION_GET_MNEMONIC_PATH_SUBSYSTEM = "get_mnemonic_path_subsystem";
+
     private String parent_uuid;
 
     public UUID getParentUuid() {
@@ -75,8 +79,12 @@ public class Subsystem extends Structure {
         return true;
     }
 
+    @Override
     public boolean equalsId(Object other) {
-        return other instanceof Subsystem && ((Subsystem) other).getId().equals(getId());
+        if (other instanceof Subsystem object) {
+            return object.getId().equals(getId());
+        }
+        return false;
     }
 
     @Override
diff --git a/src/main/java/org/openepics/names/repository/model/System.java b/src/main/java/org/openepics/names/repository/model/System.java
index 221f7ae42ce99254ac284829ce81032812171806..63a59bafd9be54d64ddb8c3994c46cf130c57dae 100644
--- a/src/main/java/org/openepics/names/repository/model/System.java
+++ b/src/main/java/org/openepics/names/repository/model/System.java
@@ -37,6 +37,10 @@ public class System extends Structure {
      */
     private static final long serialVersionUID = -4323438470765348486L;
 
+    public static final String FIELD_PARENT_UUID = "parent_uuid";
+
+    public static final String FUNCTION_GET_MNEMONIC_PATH_SYSTEM = "get_mnemonic_path_system";
+
     private String parent_uuid;
 
     public UUID getParentUuid() {
@@ -75,8 +79,12 @@ public class System extends Structure {
         return true;
     }
 
+    @Override
     public boolean equalsId(Object other) {
-        return other instanceof System && ((System) other).getId().equals(getId());
+        if (other instanceof System object) {
+            return object.getId().equals(getId());
+        }
+        return false;
     }
 
     @Override
diff --git a/src/main/java/org/openepics/names/repository/model/SystemGroup.java b/src/main/java/org/openepics/names/repository/model/SystemGroup.java
index c296257f78b492e1634fd1e1962380880d6ac35f..03f7702cd1491a3ebf876715f9d34ffdaec0b3fb 100644
--- a/src/main/java/org/openepics/names/repository/model/SystemGroup.java
+++ b/src/main/java/org/openepics/names/repository/model/SystemGroup.java
@@ -58,8 +58,12 @@ public class SystemGroup extends Structure {
         return true;
     }
 
+    @Override
     public boolean equalsId(Object other) {
-        return other instanceof SystemGroup && ((SystemGroup) other).getId().equals(getId());
+        if (other instanceof SystemGroup object) {
+            return object.getId().equals(getId());
+        }
+        return false;
     }
 
     @Override
diff --git a/src/main/java/org/openepics/names/rest/beans/response/Response.java b/src/main/java/org/openepics/names/rest/beans/response/Response.java
index 58b15877a25bf5f1d092a3adf14bba58d9bc3f78..37abeffc45c75661d7d7c31f94ec9322d3f4b245 100644
--- a/src/main/java/org/openepics/names/rest/beans/response/Response.java
+++ b/src/main/java/org/openepics/names/rest/beans/response/Response.java
@@ -35,7 +35,20 @@ public class Response {
     private static final String CONTENT_TYPE = "Content-Type";
     private static final String APP_JSON     = "application/json";
 
-    public static final HttpHeaders HEADER_JSON = new HttpHeaders();
+    private static HttpHeaders HEADER_JSON;
+
+    /**
+     * Return http header for content type json.
+     *
+     * @return http header
+     */
+    public static HttpHeaders getHeaderJson() {
+        if (HEADER_JSON == null) {
+            HEADER_JSON = new HttpHeaders();
+            HEADER_JSON.add(Response.CONTENT_TYPE, Response.APP_JSON);
+        }
+        return HEADER_JSON;
+    }
 
     @Schema(description = "Message of the response.")
     private String message = null;
@@ -44,21 +57,12 @@ public class Response {
     @Schema(description = "Field of the response for the object that was sent to server.")
     private String field = null;
 
-    /**
-     * Constructor.
-     */
-    public Response() {
-        HEADER_JSON.add(Response.CONTENT_TYPE, Response.APP_JSON);
-    }
-
     /**
      * Constructor.
      *
      * @param message response message
      */
     public Response(String message) {
-        this();
-
         this.message = message;
         this.details = "";
         this.field = "";
@@ -72,8 +76,6 @@ public class Response {
      * @param field response field
      */
     public Response(String message, String details, String field) {
-        this();
-
         this.message = message;
         this.details = details;
         this.field = field;
diff --git a/src/main/java/org/openepics/names/rest/beans/response/ResponsePage.java b/src/main/java/org/openepics/names/rest/beans/response/ResponsePage.java
index e2c0d096bf00ce92dd8bddc8ba5b6855e7ceb145..041ff73fe1bcde5f21c6e3005e0e579b82ed8d4e 100644
--- a/src/main/java/org/openepics/names/rest/beans/response/ResponsePage.java
+++ b/src/main/java/org/openepics/names/rest/beans/response/ResponsePage.java
@@ -46,7 +46,7 @@ public abstract class ResponsePage extends Response {
     /**
      * Constructor.
      */
-    public ResponsePage() {
+    protected ResponsePage() {
         super("", "", "");
     }
 
@@ -55,7 +55,7 @@ public abstract class ResponsePage extends Response {
      *
      * @param message response message
      */
-    public ResponsePage(String message) {
+    protected ResponsePage(String message) {
         super(message, "", "");
     }
 
@@ -65,7 +65,7 @@ public abstract class ResponsePage extends Response {
      * @param message response message
      * @param details response details
      */
-    public ResponsePage(String message, String details) {
+    protected ResponsePage(String message, String details) {
         super(message, details, "");
     }
 
@@ -76,7 +76,7 @@ public abstract class ResponsePage extends Response {
      * @param details response details
      * @param field response field
      */
-    public ResponsePage(String message, String details, String field) {
+    protected ResponsePage(String message, String details, String field) {
         super(message, details, field);
     }
 
diff --git a/src/main/java/org/openepics/names/rest/controller/GlobalControllerExceptionHandler.java b/src/main/java/org/openepics/names/rest/controller/GlobalControllerExceptionHandler.java
index 33014208615a15ccf592d23b16ff4c72401fc3c9..47282d1502714950378e3f73dafb21b1352c358e 100644
--- a/src/main/java/org/openepics/names/rest/controller/GlobalControllerExceptionHandler.java
+++ b/src/main/java/org/openepics/names/rest/controller/GlobalControllerExceptionHandler.java
@@ -97,7 +97,7 @@ public class GlobalControllerExceptionHandler extends ResponseEntityExceptionHan
             }
         }
 
-        return new ResponseEntity<>(response, Response.HEADER_JSON, resultStatus);
+        return new ResponseEntity<>(response, Response.getHeaderJson(), resultStatus);
     }
 
 }
diff --git a/src/main/java/org/openepics/names/rest/controller/HealthcheckController.java b/src/main/java/org/openepics/names/rest/controller/HealthcheckController.java
index c3634e3ec75f81f6fb10acff729a47a5ba7051a3..62b17beeb05da4f7ea6bcc1acc4fbceea1ca5a9a 100644
--- a/src/main/java/org/openepics/names/rest/controller/HealthcheckController.java
+++ b/src/main/java/org/openepics/names/rest/controller/HealthcheckController.java
@@ -19,7 +19,6 @@
 package org.openepics.names.rest.controller;
 
 import java.text.DateFormat;
-import java.text.SimpleDateFormat;
 import java.util.Date;
 
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
@@ -75,7 +74,7 @@ public class HealthcheckController {
         // return healthcheck as server timestamp
         //     datetime - dateStyle, timeStyle - full
 
-        return SimpleDateFormat.getDateTimeInstance(DateFormat.FULL, DateFormat.FULL).format(new Date());
+        return DateFormat.getDateTimeInstance(DateFormat.FULL, DateFormat.FULL).format(new Date());
     }
 
 }
diff --git a/src/main/java/org/openepics/names/rest/controller/NamesController.java b/src/main/java/org/openepics/names/rest/controller/NamesController.java
index 5358b5d9dfbe8d09dc095478e3a6b7ce82bef03e..5d20b5fdc6437330d1eec3ee71ba7b34ac596f52 100644
--- a/src/main/java/org/openepics/names/rest/controller/NamesController.java
+++ b/src/main/java/org/openepics/names/rest/controller/NamesController.java
@@ -63,6 +63,8 @@ public class NamesController implements INames {
 
     private static final Logger LOGGER = Logger.getLogger(NamesController.class.getName());
 
+    private static final String ATTACHMENT_FILENAME_NAME_ELEMENT_XLSX = "attachment; filename=NameElement.xlsx";
+
     private NamesService namesService;
 
     @Autowired
@@ -80,7 +82,7 @@ public class NamesController implements INames {
 
         try {
             namesService.validateNamesCreate(nameElements);
-            return new ResponseEntity<>(namesService.createNames(nameElements), Response.HEADER_JSON, HttpStatus.CREATED);
+            return new ResponseEntity<>(namesService.createNames(nameElements), Response.getHeaderJson(), HttpStatus.CREATED);
         } catch (ServiceException e) {
             LogUtil.logServiceException(LOGGER, Level.SEVERE, e);
             LogUtil.logStackTraceElements(LOGGER, Level.SEVERE, e);
@@ -106,7 +108,7 @@ public class NamesController implements INames {
                  List<NameElement> nameElements = namesService.createNames(nameElementCommands);
                  InputStreamResource isr = new InputStreamResource(ExcelUtil.nameElementsToExcel(nameElements));
                  return ResponseEntity.ok()
-                         .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=NameElement.xlsx")
+                         .header(HttpHeaders.CONTENT_DISPOSITION, ATTACHMENT_FILENAME_NAME_ELEMENT_XLSX)
                          .contentType(MediaType.parseMediaType(ExcelUtil.MIME_TYPE_EXCEL))
                          .body(isr);
              } else {
@@ -154,7 +156,7 @@ public class NamesController implements INames {
         ResponsePageNameElements nameElements = readNames(deleted, queryFields, queryValues, orderBy, isAsc, page, pageSize);
         InputStreamResource isr = new InputStreamResource(ExcelUtil.nameElementsToExcel(nameElements));
         return ResponseEntity.ok()
-                .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=NameElement.xlsx")
+                .header(HttpHeaders.CONTENT_DISPOSITION, ATTACHMENT_FILENAME_NAME_ELEMENT_XLSX)
                 .contentType(MediaType.parseMediaType(ExcelUtil.MIME_TYPE_EXCEL))
                 .body(isr);
     }
@@ -247,45 +249,45 @@ public class NamesController implements INames {
     @Override
     public ResponseEntity<ResponseBoolean> existsName(String name) {
         try {
-            return new ResponseEntity<>(new ResponseBoolean(namesService.existsName(name)), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(namesService.existsName(name)), Response.getHeaderJson(), HttpStatus.OK);
         } catch (ServiceException e) {
             LogUtil.logServiceException(LOGGER, Level.SEVERE, e);
             LogUtil.logStackTraceElements(LOGGER, Level.SEVERE, e);
-            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, e.getMessage(), e.getDetails(), e.getField()), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, e.getMessage(), e.getDetails(), e.getField()), Response.getHeaderJson(), HttpStatus.OK);
         } catch (Exception e) {
             LOGGER.log(Level.SEVERE, e.getMessage());
             LogUtil.logStackTraceElements(LOGGER, Level.SEVERE, e);
-            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED), Response.getHeaderJson(), HttpStatus.OK);
         }
     }
 
     @Override
     public ResponseEntity<ResponseBoolean> isLegacyName(String name) {
         try {
-            return new ResponseEntity<>(new ResponseBoolean(namesService.isLegacyName(name)), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(namesService.isLegacyName(name)), Response.getHeaderJson(), HttpStatus.OK);
         } catch (ServiceException e) {
             LogUtil.logServiceException(LOGGER, Level.SEVERE, e);
             LogUtil.logStackTraceElements(LOGGER, Level.SEVERE, e);
-            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, e.getMessage(), e.getDetails(), e.getField()), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, e.getMessage(), e.getDetails(), e.getField()), Response.getHeaderJson(), HttpStatus.OK);
         } catch (Exception e) {
             LOGGER.log(Level.SEVERE, e.getMessage());
             LogUtil.logStackTraceElements(LOGGER, Level.SEVERE, e);
-            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED), Response.getHeaderJson(), HttpStatus.OK);
         }
     }
 
     @Override
     public ResponseEntity<ResponseBoolean> isValidToCreateName(String name) {
         try {
-            return new ResponseEntity<>(new ResponseBoolean(namesService.isValidToCreateName(name)), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(namesService.isValidToCreateName(name)), Response.getHeaderJson(), HttpStatus.OK);
         } catch (ServiceException e) {
             LogUtil.logServiceException(LOGGER, Level.SEVERE, e);
             LogUtil.logStackTraceElements(LOGGER, Level.SEVERE, e);
-            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, e.getMessage(), e.getDetails(), e.getField()), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, e.getMessage(), e.getDetails(), e.getField()), Response.getHeaderJson(), HttpStatus.OK);
         } catch (Exception e) {
             LOGGER.log(Level.SEVERE, e.getMessage());
             LogUtil.logStackTraceElements(LOGGER, Level.SEVERE, e);
-            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED), Response.getHeaderJson(), HttpStatus.OK);
         }
     }
 
@@ -318,7 +320,7 @@ public class NamesController implements INames {
                 responses.add(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED));
             }
         }
-        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.HEADER_JSON, HttpStatus.OK);
+        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.getHeaderJson(), HttpStatus.OK);
     }
 
     @Override
@@ -348,7 +350,7 @@ public class NamesController implements INames {
                 responses.add(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED));
             }
         }
-        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.HEADER_JSON, HttpStatus.OK);
+        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.getHeaderJson(), HttpStatus.OK);
     }
 
     @Override
@@ -378,7 +380,7 @@ public class NamesController implements INames {
                 responses.add(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED));
             }
         }
-        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.HEADER_JSON, HttpStatus.OK);
+        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.getHeaderJson(), HttpStatus.OK);
     }
 
     // ----------------------------------------------------------------------------------------------------
@@ -418,7 +420,7 @@ public class NamesController implements INames {
                 List<NameElement> nameElements = namesService.updateNames(nameElementCommands);
                 InputStreamResource isr = new InputStreamResource(ExcelUtil.nameElementsToExcel(nameElements));
                 return ResponseEntity.ok()
-                        .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=NameElement.xlsx")
+                        .header(HttpHeaders.CONTENT_DISPOSITION, ATTACHMENT_FILENAME_NAME_ELEMENT_XLSX)
                         .contentType(MediaType.parseMediaType(ExcelUtil.MIME_TYPE_EXCEL))
                         .body(isr);
             } else {
@@ -476,7 +478,7 @@ public class NamesController implements INames {
                 List<NameElement> nameElements = namesService.deleteNames(nameElementCommands);
                 InputStreamResource isr = new InputStreamResource(ExcelUtil.nameElementsToExcel(nameElements));
                 return ResponseEntity.ok()
-                        .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=NameElement.xlsx")
+                        .header(HttpHeaders.CONTENT_DISPOSITION, ATTACHMENT_FILENAME_NAME_ELEMENT_XLSX)
                         .contentType(MediaType.parseMediaType(ExcelUtil.MIME_TYPE_EXCEL))
                         .body(isr);
             } else {
diff --git a/src/main/java/org/openepics/names/rest/controller/StructuresController.java b/src/main/java/org/openepics/names/rest/controller/StructuresController.java
index 047ec6ca33d9a220caf7c9a4950dfa8b66f287ef..20cda037aa3fc27f0eec185ad5cd95b478e8fc93 100644
--- a/src/main/java/org/openepics/names/rest/controller/StructuresController.java
+++ b/src/main/java/org/openepics/names/rest/controller/StructuresController.java
@@ -72,6 +72,8 @@ public class StructuresController implements IStructures {
 
     private static final Logger LOGGER = Logger.getLogger(StructuresController.class.getName());
 
+    private static final String ATTACHMENT_FILENAME_STRUCTURE_ELEMENT_XLSX = "attachment; filename=StructureElement.xlsx";
+
     private StructuresService structuresService;
 
     @Autowired
@@ -89,7 +91,7 @@ public class StructuresController implements IStructures {
 
         try {
             structuresService.validateStructuresCreate(structureElements);
-            return new ResponseEntity<>(structuresService.createStructures(structureElements), Response.HEADER_JSON, HttpStatus.CREATED);
+            return new ResponseEntity<>(structuresService.createStructures(structureElements), Response.getHeaderJson(), HttpStatus.CREATED);
         } catch (ServiceException e) {
             LogUtil.logServiceException(LOGGER, Level.SEVERE, e);
             LogUtil.logStackTraceElements(LOGGER, Level.SEVERE, e);
@@ -115,7 +117,7 @@ public class StructuresController implements IStructures {
                 List<StructureElement> structureElements = structuresService.createStructures(structureElementCommands);
                 InputStreamResource isr = new InputStreamResource(ExcelUtil.structureElementsToExcel(structureElements));
                 return ResponseEntity.ok()
-                        .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=StructureElement.xlsx")
+                        .header(HttpHeaders.CONTENT_DISPOSITION, ATTACHMENT_FILENAME_STRUCTURE_ELEMENT_XLSX)
                         .contentType(MediaType.parseMediaType(ExcelUtil.MIME_TYPE_EXCEL))
                         .body(isr);
             } else {
@@ -164,7 +166,7 @@ public class StructuresController implements IStructures {
         ResponsePageStructureElements structureElements = readStructures(type, statuses, deleted, queryFields, queryValues, orderBy, isAsc, page, pageSize);
         InputStreamResource isr = new InputStreamResource(ExcelUtil.structureElementsToExcel(structureElements));
         return ResponseEntity.ok()
-                .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=StructureElement.xlsx")
+                .header(HttpHeaders.CONTENT_DISPOSITION, ATTACHMENT_FILENAME_STRUCTURE_ELEMENT_XLSX)
                 .contentType(MediaType.parseMediaType(ExcelUtil.MIME_TYPE_EXCEL))
                 .body(isr);
     }
@@ -261,30 +263,30 @@ public class StructuresController implements IStructures {
     @Override
     public ResponseEntity<ResponseBoolean> existsStructure(Type type, String mnemonicpath) {
         try {
-            return new ResponseEntity<>(new ResponseBoolean(structuresService.existsStructure(type, mnemonicpath)), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(structuresService.existsStructure(type, mnemonicpath)), Response.getHeaderJson(), HttpStatus.OK);
         } catch (ServiceException e) {
             LogUtil.logServiceException(LOGGER, Level.SEVERE, e);
             LogUtil.logStackTraceElements(LOGGER, Level.SEVERE, e);
-            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, e.getMessage(), e.getDetails(), e.getField()), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, e.getMessage(), e.getDetails(), e.getField()), Response.getHeaderJson(), HttpStatus.OK);
         } catch (Exception e) {
             LOGGER.log(Level.SEVERE, e.getMessage());
             LogUtil.logStackTraceElements(LOGGER, Level.SEVERE, e);
-            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED), Response.getHeaderJson(), HttpStatus.OK);
         }
     }
 
     @Override
     public ResponseEntity<ResponseBoolean> isValidToCreateStructure(Type type, String mnemonicpath) {
         try {
-            return new ResponseEntity<>(new ResponseBoolean(structuresService.isValidToCreateStructure(type, mnemonicpath)), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(structuresService.isValidToCreateStructure(type, mnemonicpath)), Response.getHeaderJson(), HttpStatus.OK);
         } catch (ServiceException e) {
             LogUtil.logServiceException(LOGGER, Level.SEVERE, e);
             LogUtil.logStackTraceElements(LOGGER, Level.SEVERE, e);
-            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, e.getMessage(), e.getDetails(), e.getField()), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, e.getMessage(), e.getDetails(), e.getField()), Response.getHeaderJson(), HttpStatus.OK);
         } catch (Exception e) {
             LOGGER.log(Level.SEVERE, e.getMessage());
             LogUtil.logStackTraceElements(LOGGER, Level.SEVERE, e);
-            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED), Response.HEADER_JSON, HttpStatus.OK);
+            return new ResponseEntity<>(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED), Response.getHeaderJson(), HttpStatus.OK);
         }
     }
 
@@ -317,7 +319,7 @@ public class StructuresController implements IStructures {
                 responses.add(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED));
             }
         }
-        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.HEADER_JSON, HttpStatus.OK);
+        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.getHeaderJson(), HttpStatus.OK);
     }
 
     @Override
@@ -347,7 +349,7 @@ public class StructuresController implements IStructures {
                 responses.add(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED));
             }
         }
-        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.HEADER_JSON, HttpStatus.OK);
+        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.getHeaderJson(), HttpStatus.OK);
     }
 
     @Override
@@ -377,7 +379,7 @@ public class StructuresController implements IStructures {
                 responses.add(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED));
             }
         }
-        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.HEADER_JSON, HttpStatus.OK);
+        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.getHeaderJson(), HttpStatus.OK);
     }
 
     @Override
@@ -407,7 +409,7 @@ public class StructuresController implements IStructures {
                 responses.add(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED));
             }
         }
-        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.HEADER_JSON, HttpStatus.OK);
+        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.getHeaderJson(), HttpStatus.OK);
     }
 
     @Override
@@ -437,7 +439,7 @@ public class StructuresController implements IStructures {
                 responses.add(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED));
             }
         }
-        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.HEADER_JSON, HttpStatus.OK);
+        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.getHeaderJson(), HttpStatus.OK);
     }
 
     @Override
@@ -467,7 +469,7 @@ public class StructuresController implements IStructures {
                 responses.add(new ResponseBoolean(Boolean.FALSE, TextUtil.OPERATION_COULD_NOT_BE_PERFORMED));
             }
         }
-        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.HEADER_JSON, HttpStatus.OK);
+        return new ResponseEntity<>(new ResponseBooleanList(responses, Boolean.valueOf(response), reason), Response.getHeaderJson(), HttpStatus.OK);
     }
 
     // ----------------------------------------------------------------------------------------------------
@@ -497,7 +499,7 @@ public class StructuresController implements IStructures {
                 List<StructureElement> structureElements = structuresService.updateStructures(structureElementCommands);
                 InputStreamResource isr = new InputStreamResource(ExcelUtil.structureElementsToExcel(structureElements));
                 return ResponseEntity.ok()
-                        .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=StructureElement.xlsx")
+                        .header(HttpHeaders.CONTENT_DISPOSITION, ATTACHMENT_FILENAME_STRUCTURE_ELEMENT_XLSX)
                         .contentType(MediaType.parseMediaType(ExcelUtil.MIME_TYPE_EXCEL))
                         .body(isr);
             } else {
@@ -545,7 +547,7 @@ public class StructuresController implements IStructures {
                 List<StructureElement> structureElements = structuresService.deleteStructures(structureElementCommands);
                 InputStreamResource isr = new InputStreamResource(ExcelUtil.structureElementsToExcel(structureElements));
                 return ResponseEntity.ok()
-                        .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=StructureElement.xlsx")
+                        .header(HttpHeaders.CONTENT_DISPOSITION, ATTACHMENT_FILENAME_STRUCTURE_ELEMENT_XLSX)
                         .contentType(MediaType.parseMediaType(ExcelUtil.MIME_TYPE_EXCEL))
                         .body(isr);
             } else {
@@ -593,7 +595,7 @@ public class StructuresController implements IStructures {
                 List<StructureElement> structureElements = structuresService.approveStructures(structureElementCommands);
                 InputStreamResource isr = new InputStreamResource(ExcelUtil.structureElementsToExcel(structureElements));
                 return ResponseEntity.ok()
-                        .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=StructureElement.xlsx")
+                        .header(HttpHeaders.CONTENT_DISPOSITION, ATTACHMENT_FILENAME_STRUCTURE_ELEMENT_XLSX)
                         .contentType(MediaType.parseMediaType(ExcelUtil.MIME_TYPE_EXCEL))
                         .body(isr);
             } else {
@@ -639,7 +641,7 @@ public class StructuresController implements IStructures {
                 List<StructureElement> structureElements = structuresService.cancelStructures(structureElementCommands);
                 InputStreamResource isr = new InputStreamResource(ExcelUtil.structureElementsToExcel(structureElements));
                 return ResponseEntity.ok()
-                        .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=StructureElement.xlsx")
+                        .header(HttpHeaders.CONTENT_DISPOSITION, ATTACHMENT_FILENAME_STRUCTURE_ELEMENT_XLSX)
                         .contentType(MediaType.parseMediaType(ExcelUtil.MIME_TYPE_EXCEL))
                         .body(isr);
             } else {
@@ -685,7 +687,7 @@ public class StructuresController implements IStructures {
                 List<StructureElement> structureElements = structuresService.rejectStructures(structureElementCommands);
                 InputStreamResource isr = new InputStreamResource(ExcelUtil.structureElementsToExcel(structureElements));
                 return ResponseEntity.ok()
-                        .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=StructureElement.xlsx")
+                        .header(HttpHeaders.CONTENT_DISPOSITION, ATTACHMENT_FILENAME_STRUCTURE_ELEMENT_XLSX)
                         .contentType(MediaType.parseMediaType(ExcelUtil.MIME_TYPE_EXCEL))
                         .body(isr);
             } else {
diff --git a/src/main/java/org/openepics/names/rest/controller/VerificationController.java b/src/main/java/org/openepics/names/rest/controller/VerificationController.java
index efca0fe53ab895d741bca2cf9a5a54415ac0ae9f..b28eeea2ed40751f02cf9542a99d363ad1f2d595 100644
--- a/src/main/java/org/openepics/names/rest/controller/VerificationController.java
+++ b/src/main/java/org/openepics/names/rest/controller/VerificationController.java
@@ -226,7 +226,6 @@ public class VerificationController {
         boolean check = false;
         DeviceRevision deviceRevision = null;
         for (Name name : names) {
-            check = true;
             deviceRevision = mapIdDeviceRevision.get(name.getId());
 
             check = deviceRevision != null;
@@ -298,7 +297,7 @@ public class VerificationController {
         //     all entries ok
         //     no entry nok
         boolean ok = id_ok_deviceRevisionDevice.size() == names.size()
-                && id_nok_deviceRevisionDevice.size() == 0;
+                && id_nok_deviceRevisionDevice.isEmpty();
 
         prepareLogReport("readMigrationDeviceRevision, check, after,  id_ok_deviceRevisionDevice.size:  " + id_ok_deviceRevisionDevice.size(), reportHtml);
         prepareLogReport("readMigrationDeviceRevision, check, after,  id_nok_deviceRevisionDevice.size: " + id_nok_deviceRevisionDevice.size(), reportHtml);
@@ -469,7 +468,6 @@ public class VerificationController {
         boolean check = false;
         NamePartRevision namePartRevision = null;
         for (SystemGroup systemGroup : systemGroups) {
-            check = true;
             namePartRevision = mapIdNamePartRevision.get(systemGroup.getId());
 
             check = namePartRevision != null;
@@ -518,7 +516,6 @@ public class VerificationController {
         // check entry by entry
         //         each attribute as expected
         for (System system : systems) {
-            check = true;
             namePartRevision = mapIdNamePartRevision.get(system.getId());
 
             check = namePartRevision != null;
@@ -568,7 +565,6 @@ public class VerificationController {
         // check entry by entry
         //         each attribute as expected
         for (Subsystem subsystem : subsystems) {
-            check = true;
             namePartRevision = mapIdNamePartRevision.get(subsystem.getId());
 
             check = namePartRevision != null;
@@ -618,7 +614,6 @@ public class VerificationController {
         // check entry by entry
         //         each attribute as expected
         for (Discipline discipline : disciplines) {
-            check = true;
             namePartRevision = mapIdNamePartRevision.get(discipline.getId());
 
             check = namePartRevision != null;
@@ -667,7 +662,6 @@ public class VerificationController {
         // check entry by entry
         //         each attribute as expected
         for (DeviceGroup deviceGroup : deviceGroups) {
-            check = true;
             namePartRevision = mapIdNamePartRevision.get(deviceGroup.getId());
 
             check = namePartRevision != null;
@@ -717,7 +711,6 @@ public class VerificationController {
         // check entry by entry
         //         each attribute as expected
         for (DeviceType deviceType : deviceTypes) {
-            check = true;
             namePartRevision = mapIdNamePartRevision.get(deviceType.getId());
 
             check = namePartRevision != null;
@@ -767,7 +760,7 @@ public class VerificationController {
         //     all entries ok
         //     no entry nok
         boolean ok = id_ok_namePartRevision.size() == namePartRevisions.size()
-                && id_nok_namePartRevision.size() == 0;
+                && id_nok_namePartRevision.isEmpty();
 
         prepareLogReport("readMigrationNamePartRevision, check, after,             id_ok_namePartRevision.size:  " + id_ok_namePartRevision.size(), reportHtml);
         prepareLogReport("readMigrationNamePartRevision, check, after,             id_nok_namePartRevision.size: " + id_nok_namePartRevision.size(), reportHtml);
@@ -985,7 +978,6 @@ public class VerificationController {
                 countIdInOld++;
             } else if (!idInOld) {
                 countNotIdInOld++;
-                // break;
             }
             mapIdDeviceRevisionDifference.remove(name.getId());
         }
@@ -1023,7 +1015,7 @@ public class VerificationController {
         prepareLogReport("readRestApiOldVsNew, check, after difference 2, listDeviceRevisionWrong.size:                        " + listDeviceRevisionWrong.size(), reportHtml);
 
         boolean ok = (mapIdDeviceRevisionDifference.size() == (nameViewProvider.getNameRevisions().entrySet().size() - names.size()))
-                && (listDeviceRevisionWrong.size() == 0);
+                && listDeviceRevisionWrong.isEmpty();
 
         prepareLogReport("readRestApiOldVsNew, check, after", reportHtml);
         prepareLogReport("readRestApiOldVsNew, ok: " + ok, reportHtml);
diff --git a/src/main/java/org/openepics/names/rest/controller/old/DeviceNamesControllerV0.java b/src/main/java/org/openepics/names/rest/controller/old/DeviceNamesControllerV0.java
index d7495328b3fc34d1317fdd536ff781973b2e97b3..613d83bf8f3b25f66735c0f9b91afe8c1a402a7b 100644
--- a/src/main/java/org/openepics/names/rest/controller/old/DeviceNamesControllerV0.java
+++ b/src/main/java/org/openepics/names/rest/controller/old/DeviceNamesControllerV0.java
@@ -123,7 +123,7 @@ public class DeviceNamesControllerV0 {
             deviceNameElements.add(DeviceNameElementUtil.getDeviceNameElement(name, holder));
         }
 
-        LOGGER.log(Level.INFO, "findNames, deviceNameElements.size: " + deviceNameElements.size());
+        LOGGER.log(Level.INFO, "findNames, deviceNameElements.size: {0}", deviceNameElements.size());
 
         return deviceNameElements;
     }
@@ -167,8 +167,8 @@ public class DeviceNamesControllerV0 {
             }
         }
 
-        LOGGER.log(Level.INFO, "findNamesSearch, name:                    " + name);
-        LOGGER.log(Level.INFO, "findNamesSearch, deviceNameElements.size: " + deviceNameElements.size());
+        LOGGER.log(Level.INFO, "findNamesSearch, name:                    {0}", name);
+        LOGGER.log(Level.INFO, "findNamesSearch, deviceNameElements.size: {0}", deviceNameElements.size());
 
         return deviceNameElements;
     }
@@ -203,8 +203,8 @@ public class DeviceNamesControllerV0 {
             deviceNameElements.add(DeviceNameElementUtil.getDeviceNameElement(name, holder));
         }
 
-        LOGGER.log(Level.INFO, "findNamesBySystem, system:                  " + system);
-        LOGGER.log(Level.INFO, "findNamesBySystem, deviceNameElements.size: " + deviceNameElements.size());
+        LOGGER.log(Level.INFO, "findNamesBySystem, system:                  {0}", system);
+        LOGGER.log(Level.INFO, "findNamesBySystem, deviceNameElements.size: {0}", deviceNameElements.size());
 
         return deviceNameElements;
     }
@@ -244,8 +244,8 @@ public class DeviceNamesControllerV0 {
             }
         }
 
-        LOGGER.log(Level.INFO, "findNamesSearch, system:                  " + system);
-        LOGGER.log(Level.INFO, "findNamesSearch, deviceNameElements.size: " + deviceNameElements.size());
+        LOGGER.log(Level.INFO, "findNamesSearch, system:                  {0}", system);
+        LOGGER.log(Level.INFO, "findNamesSearch, deviceNameElements.size: {0}", deviceNameElements.size());
 
         return deviceNameElements;
     }
@@ -277,8 +277,8 @@ public class DeviceNamesControllerV0 {
             }
         }
 
-        LOGGER.log(Level.INFO, "findNamesBySubsystem, subsystem:               " + subsystem);
-        LOGGER.log(Level.INFO, "findNamesBySubsystem, deviceNameElements.size: " + deviceNameElements.size());
+        LOGGER.log(Level.INFO, "findNamesBySubsystem, subsystem:               {0}", subsystem);
+        LOGGER.log(Level.INFO, "findNamesBySubsystem, deviceNameElements.size: {0}", deviceNameElements.size());
 
         return deviceNameElements;
     }
@@ -318,8 +318,8 @@ public class DeviceNamesControllerV0 {
             }
         }
 
-        LOGGER.log(Level.INFO, "findNamesBySubsystemSearch, subsystem:               " + subsystem);
-        LOGGER.log(Level.INFO, "findNamesBySubsystemSearch, deviceNameElements.size: " + deviceNameElements.size());
+        LOGGER.log(Level.INFO, "findNamesBySubsystemSearch, subsystem:               {0}", subsystem);
+        LOGGER.log(Level.INFO, "findNamesBySubsystemSearch, deviceNameElements.size: {0}", deviceNameElements.size());
 
         return deviceNameElements;
     }
@@ -351,8 +351,8 @@ public class DeviceNamesControllerV0 {
             }
         }
 
-        LOGGER.log(Level.INFO, "findNamesByDiscipline, discipline:              " + discipline);
-        LOGGER.log(Level.INFO, "findNamesByDiscipline, deviceNameElements.size: " + deviceNameElements.size());
+        LOGGER.log(Level.INFO, "findNamesByDiscipline, discipline:              {0}", discipline);
+        LOGGER.log(Level.INFO, "findNamesByDiscipline, deviceNameElements.size: {0}", deviceNameElements.size());
 
         return deviceNameElements;
     }
@@ -392,8 +392,8 @@ public class DeviceNamesControllerV0 {
             }
         }
 
-        LOGGER.log(Level.INFO, "findNamesByDisciplineSearch, discipline:              " + discipline);
-        LOGGER.log(Level.INFO, "findNamesByDisciplineSearch, deviceNameElements.size: " + deviceNameElements.size());
+        LOGGER.log(Level.INFO, "findNamesByDisciplineSearch, discipline:              {0}", discipline);
+        LOGGER.log(Level.INFO, "findNamesByDisciplineSearch, deviceNameElements.size: {0}", deviceNameElements.size());
 
         return deviceNameElements;
     }
@@ -425,8 +425,8 @@ public class DeviceNamesControllerV0 {
             }
         }
 
-        LOGGER.log(Level.INFO, "findNamesByDeviceType, deviceType:              " + deviceType);
-        LOGGER.log(Level.INFO, "findNamesByDeviceType, deviceNameElements.size: " + deviceNameElements.size());
+        LOGGER.log(Level.INFO, "findNamesByDeviceType, deviceType:              {0}", deviceType);
+        LOGGER.log(Level.INFO, "findNamesByDeviceType, deviceNameElements.size: {0}", deviceNameElements.size());
 
         return deviceNameElements;
     }
@@ -466,8 +466,8 @@ public class DeviceNamesControllerV0 {
             }
         }
 
-        LOGGER.log(Level.INFO, "findNamesByDeviceTypeSearch, deviceType:              " + deviceType);
-        LOGGER.log(Level.INFO, "findNamesByDeviceTypeSearch, deviceNameElements.size: " + deviceNameElements.size());
+        LOGGER.log(Level.INFO, "findNamesByDeviceTypeSearch, deviceType:              {0}", deviceType);
+        LOGGER.log(Level.INFO, "findNamesByDeviceTypeSearch, deviceNameElements.size: {0}", deviceNameElements.size());
 
         return deviceNameElements;
     }
@@ -493,8 +493,8 @@ public class DeviceNamesControllerV0 {
         }
         DeviceNameElement deviceNameElement = DeviceNameElementUtil.getDeviceNameElement(name, holderIRepositories);
 
-        LOGGER.log(Level.INFO, "findName, uuid:              " + uuid);
-        LOGGER.log(Level.INFO, "findName, deviceNameElement: " + deviceNameElement);
+        LOGGER.log(Level.INFO, "findName, uuid:              {0}", uuid);
+        LOGGER.log(Level.INFO, "findName, deviceNameElement: {0}", deviceNameElement);
 
         return deviceNameElement;
     }
diff --git a/src/main/java/org/openepics/names/rest/controller/old/HealthcheckControllerV0.java b/src/main/java/org/openepics/names/rest/controller/old/HealthcheckControllerV0.java
index e3414474df0c13e160a95c33825a4e21b027b837..3eba05f03dc8fd5c3d1397bb1bc6987850947883 100644
--- a/src/main/java/org/openepics/names/rest/controller/old/HealthcheckControllerV0.java
+++ b/src/main/java/org/openepics/names/rest/controller/old/HealthcheckControllerV0.java
@@ -19,7 +19,6 @@
 package org.openepics.names.rest.controller.old;
 
 import java.text.DateFormat;
-import java.text.SimpleDateFormat;
 import java.util.Date;
 
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
@@ -59,7 +58,7 @@ public class HealthcheckControllerV0 {
         // return healthcheck as server timestamp
         //     datetime - dateStyle, timeStyle - full
 
-        return SimpleDateFormat.getDateTimeInstance(DateFormat.FULL, DateFormat.FULL).format(new Date());
+        return DateFormat.getDateTimeInstance(DateFormat.FULL, DateFormat.FULL).format(new Date());
     }
 
 }
diff --git a/src/main/java/org/openepics/names/rest/controller/old/HistoryControllerV0.java b/src/main/java/org/openepics/names/rest/controller/old/HistoryControllerV0.java
index 99cf1337c06442fa12891c15575dcc840243dcde..265d075f45d43321153228d34bfd91fdba42f758 100644
--- a/src/main/java/org/openepics/names/rest/controller/old/HistoryControllerV0.java
+++ b/src/main/java/org/openepics/names/rest/controller/old/HistoryControllerV0.java
@@ -224,8 +224,8 @@ public class HistoryControllerV0 {
             }
         }
 
-        LOGGER.log(Level.INFO, "findNamePartHistoryForUuid, uuid:                 " + uuid);
-        LOGGER.log(Level.INFO, "findNamePartHistoryForUuid, historyElements.size: " + historyElements.size());
+        LOGGER.log(Level.INFO, "findNamePartHistoryForUuid, uuid:                 {0}", uuid);
+        LOGGER.log(Level.INFO, "findNamePartHistoryForUuid, historyElements.size: {0}", historyElements.size());
 
         return historyElements;
     }
@@ -256,8 +256,8 @@ public class HistoryControllerV0 {
             historyElements.add(HistoryElementUtil.getHistoryElement(name));
         }
 
-        LOGGER.log(Level.INFO, "findNameHistoryForUuid, uuid:                 " + uuid);
-        LOGGER.log(Level.INFO, "findNameHistoryForUuid, historyElements.size: " + historyElements.size());
+        LOGGER.log(Level.INFO, "findNameHistoryForUuid, uuid:                 {0}", uuid);
+        LOGGER.log(Level.INFO, "findNameHistoryForUuid, historyElements.size: {0}", historyElements.size());
 
         return historyElements;
     }
diff --git a/src/main/java/org/openepics/names/rest/controller/old/PartControllerV0.java b/src/main/java/org/openepics/names/rest/controller/old/PartControllerV0.java
index 70f8fb951b077d85653b4c5c468e5e8cf2a4703d..9c34b77d27ca0f7fba34c061bf1c378d7666c583 100644
--- a/src/main/java/org/openepics/names/rest/controller/old/PartControllerV0.java
+++ b/src/main/java/org/openepics/names/rest/controller/old/PartControllerV0.java
@@ -141,8 +141,8 @@ public class PartControllerV0 {
             partElements.add(PartElementUtil.getPartElement(deviceType, holderIRepositories));
         }
 
-        LOGGER.log(Level.INFO, "findPartsByMnemonic, mnemonic:          " + mnemonic);
-        LOGGER.log(Level.INFO, "findPartsByMnemonic, partElements.size: " + partElements.size());
+        LOGGER.log(Level.INFO, "findPartsByMnemonic, mnemonic:          {0}", mnemonic);
+        LOGGER.log(Level.INFO, "findPartsByMnemonic, partElements.size: {0}", partElements.size());
 
         return partElements;
     }
@@ -213,8 +213,8 @@ public class PartControllerV0 {
             }
         }
 
-        LOGGER.log(Level.INFO, "getAllPartsByMnemonicSearch, mnemonic:          " + mnemonic);
-        LOGGER.log(Level.INFO, "getAllPartsByMnemonicSearch, partElements.size: " + partElements.size());
+        LOGGER.log(Level.INFO, "getAllPartsByMnemonicSearch, mnemonic:          {0}", mnemonic);
+        LOGGER.log(Level.INFO, "getAllPartsByMnemonicSearch, partElements.size: {0}", partElements.size());
 
         return partElements;
     }
@@ -293,8 +293,8 @@ public class PartControllerV0 {
             }
         }
 
-        LOGGER.log(Level.INFO, "findPartsByMnemonicPathSearch, mnemonicPath:      " + mnemonicPath);
-        LOGGER.log(Level.INFO, "findPartsByMnemonicPathSearch, partElements.size: " + partElements.size());
+        LOGGER.log(Level.INFO, "findPartsByMnemonicPathSearch, mnemonicPath:      {0}", mnemonicPath);
+        LOGGER.log(Level.INFO, "findPartsByMnemonicPathSearch, partElements.size: {0}", partElements.size());
 
         return partElements;
     }
diff --git a/src/main/java/org/openepics/names/rest/filter/RestLogFilter.java b/src/main/java/org/openepics/names/rest/filter/RestLogFilter.java
index 1a5269ac906985a811c79a4e2a63791492841441..f1755abf6d0bf89d8e2fc9d145e7aaa3e7d8ce03 100644
--- a/src/main/java/org/openepics/names/rest/filter/RestLogFilter.java
+++ b/src/main/java/org/openepics/names/rest/filter/RestLogFilter.java
@@ -166,8 +166,8 @@ public class RestLogFilter implements Filter {
     public void doFilter(final ServletRequest request, final ServletResponse response, final FilterChain filterChain)
             throws IOException, ServletException {
         HttpServletRequest req = null;
-        if (request instanceof HttpServletRequest) {
-            req = (HttpServletRequest)request;
+        if (request instanceof HttpServletRequest object) {
+            req = object;
         }
 
         LogEntry logLine = new LogEntry();
@@ -190,8 +190,8 @@ public class RestLogFilter implements Filter {
             logLine.setTime(endTime - startTime);
 
             HttpServletResponse resp = null;
-            if (response instanceof HttpServletResponse) {
-                resp = (HttpServletResponse) response;
+            if (response instanceof HttpServletResponse object) {
+                resp = object;
             }
 
             if (resp != null) {
diff --git a/src/main/java/org/openepics/names/service/NamesService.java b/src/main/java/org/openepics/names/service/NamesService.java
index a7dff5e0ff1cac26af3c3b77017ab96518c4e0da..c6f8a1771fb6b10e357169efec27e0d0ef8f454c 100644
--- a/src/main/java/org/openepics/names/service/NamesService.java
+++ b/src/main/java/org/openepics/names/service/NamesService.java
@@ -144,7 +144,7 @@ public class NamesService {
         //     return
         //         name elements for created names
 
-        LOGGER.log(Level.INFO, "createNames, nameElements.size:        " + String.valueOf(nameElements != null ? nameElements.size() : "null"));
+        LOGGER.log(Level.INFO, "createNames, nameElements.size:        {0}", String.valueOf(nameElements != null ? nameElements.size() : "null"));
 
         // initiate holder of containers for system and device structure content, for performance reasons
         HolderSystemDeviceStructure holder = new HolderSystemDeviceStructure(holderIRepositories);
@@ -157,7 +157,7 @@ public class NamesService {
             createdNameElements.add(createName(nameElement, holder, requestedBy));
         }
 
-        LOGGER.log(Level.INFO, "createNames, createdNameElements.size: " + createdNameElements.size());
+        LOGGER.log(Level.INFO, "createNames, createdNameElements.size: {0}", createdNameElements.size());
         return createdNameElements;
     }
     @Transactional(propagation = Propagation.MANDATORY)
@@ -215,22 +215,22 @@ public class NamesService {
             Boolean deleted, FieldName[] queryFields, String[] queryValues, Boolean includeHistory,
             FieldName orderBy, Boolean isAsc, Integer offset, Integer limit) {
 
-        LOGGER.log(Level.INFO, "readNames, deleted:            " + deleted);
-        LOGGER.log(Level.INFO, "readNames, queryFields.length: " + String.valueOf(queryFields != null ? queryFields.length : "null"));
-        LOGGER.log(Level.INFO, "readNames, queryValues.length: " + String.valueOf(queryValues != null ? queryValues.length : "null"));
-        LOGGER.log(Level.INFO, "readNames, includeHistory:     " + includeHistory);
-        LOGGER.log(Level.INFO, "readNames, orderBy:            " + orderBy);
-        LOGGER.log(Level.INFO, "readNames, isAsc:              " + isAsc);
-        LOGGER.log(Level.INFO, "readNames, offset:             " + offset);
-        LOGGER.log(Level.INFO, "readNames, limit:              " + limit);
+        LOGGER.log(Level.INFO, "readNames, deleted:            {0}", deleted);
+        LOGGER.log(Level.INFO, "readNames, queryFields.length: {0}", String.valueOf(queryFields != null ? queryFields.length : "null"));
+        LOGGER.log(Level.INFO, "readNames, queryValues.length: {0}", String.valueOf(queryValues != null ? queryValues.length : "null"));
+        LOGGER.log(Level.INFO, "readNames, includeHistory:     {0}", includeHistory);
+        LOGGER.log(Level.INFO, "readNames, orderBy:            {0}", orderBy);
+        LOGGER.log(Level.INFO, "readNames, isAsc:              {0}", isAsc);
+        LOGGER.log(Level.INFO, "readNames, offset:             {0}", offset);
+        LOGGER.log(Level.INFO, "readNames, limit:              {0}", limit);
         if (queryFields != null && queryFields.length > 0) {
             for (FieldName queryField : queryFields) {
-                LOGGER.log(Level.INFO, "readNames, queryField:         " + queryField);
+                LOGGER.log(Level.INFO, "readNames, queryField:         {0}", queryField);
             }
         }
         if (queryValues != null && queryValues.length > 0) {
             for (String queryValue : queryValues) {
-                LOGGER.log(Level.INFO, "readNames, queryValue:         " + queryValue);
+                LOGGER.log(Level.INFO, "readNames, queryValue:         {0}", queryValue);
             }
         }
 
@@ -259,7 +259,7 @@ public class NamesService {
         }
 
         ResponsePageNameElements response = new ResponsePageNameElements(nameElements, totalCount, nameElements.size(), offset, limit);
-        LOGGER.log(Level.INFO, "readNames, response:           " + response);
+        LOGGER.log(Level.INFO, "readNames, response:           {0}", response);
         return response;
     }
 
@@ -267,7 +267,7 @@ public class NamesService {
             String name,
             FieldName orderBy, Boolean isAsc, Integer offset, Integer limit) {
 
-        LOGGER.log(Level.INFO, "readNames, name:              " + name);
+        LOGGER.log(Level.INFO, "readNames, name:              {0}", name);
 
         // validate input
         //     name or uuid
@@ -300,7 +300,7 @@ public class NamesService {
             String mnemonicpath,
             FieldName orderBy, Boolean isAsc, Integer offset, Integer limit) {
 
-        LOGGER.log(Level.INFO, "readNamesSystemStructure, mnemonicpath: " + mnemonicpath);
+        LOGGER.log(Level.INFO, "readNamesSystemStructure, mnemonicpath: {0}", mnemonicpath);
 
         // validate input
         //     mnemonic path
@@ -320,7 +320,7 @@ public class NamesService {
             String mnemonicpath,
             FieldName orderBy, Boolean isAsc, Integer offset, Integer limit) {
 
-        LOGGER.log(Level.INFO, "readNamesDeviceStructure, mnemonicpath: " + mnemonicpath);
+        LOGGER.log(Level.INFO, "readNamesDeviceStructure, mnemonicpath: {0}", mnemonicpath);
 
         // validate input
         //     mnemonic path
@@ -339,7 +339,7 @@ public class NamesService {
     public ResponsePageNameElements readNamesHistory(
             String uuid,
             FieldName orderBy, Boolean isAsc, Integer offset, Integer limit) {
-        LOGGER.log(Level.INFO, "readNamesHistory, uuid:              " + uuid);
+        LOGGER.log(Level.INFO, "readNamesHistory, uuid:              {0}", uuid);
 
         // note
         //     HolderIRepositories and HolderSystemDeviceStructure may or may not be used for preparation of what to return
@@ -368,7 +368,7 @@ public class NamesService {
     // ----------------------------------------------------------------------------------------------------
 
     public String equivalenceName(String name) {
-        LOGGER.log(Level.INFO, "equivalenceName, name: " + name);
+        LOGGER.log(Level.INFO, "equivalenceName, name: {0}", name);
 
         // validate input
         // do
@@ -382,7 +382,7 @@ public class NamesService {
     }
 
     public Boolean existsName(String name) {
-        LOGGER.log(Level.INFO, "existsName, name: " + name);
+        LOGGER.log(Level.INFO, "existsName, name: {0}", name);
 
         // validate input
         // do
@@ -397,7 +397,7 @@ public class NamesService {
     }
 
     public Boolean isLegacyName(String name) {
-        LOGGER.log(Level.INFO, "isLegacyName, name: " + name);
+        LOGGER.log(Level.INFO, "isLegacyName, name: {0}", name);
 
         // validate input
         // do
@@ -493,7 +493,7 @@ public class NamesService {
     }
 
     public Boolean isValidToCreateName(String name) {
-        LOGGER.log(Level.INFO, "isValidToCreateName, name: " + name);
+        LOGGER.log(Level.INFO, "isValidToCreateName, name: {0}", name);
 
         // validate input
         // validate data
@@ -624,7 +624,7 @@ public class NamesService {
         //     return
         //         name elements for updated names
 
-        LOGGER.log(Level.INFO, "updateNames, nameElements.size:        " + String.valueOf(nameElements != null ? nameElements.size() : "null"));
+        LOGGER.log(Level.INFO, "updateNames, nameElements.size:        {0}", String.valueOf(nameElements != null ? nameElements.size() : "null"));
 
         // initiate holder of containers for system and device structure content, for performance reasons
         HolderSystemDeviceStructure holder = new HolderSystemDeviceStructure(holderIRepositories);
@@ -687,7 +687,7 @@ public class NamesService {
             updatedNameElements.add(NameElementUtil.getNameElement(name));
         }
 
-        LOGGER.log(Level.INFO, "updateNames, updatedNameElements.size: " + updatedNameElements.size());
+        LOGGER.log(Level.INFO, "updateNames, updatedNameElements.size: {0}", updatedNameElements.size());
         return updatedNameElements;
     }
 
@@ -705,7 +705,7 @@ public class NamesService {
         //     return
         //         name element for deleted name
 
-        LOGGER.log(Level.INFO, "deleteNames, nameElements.size:        " + String.valueOf(nameElements != null ? nameElements.size() : "null"));
+        LOGGER.log(Level.INFO, "deleteNames, nameElements.size:        {0}", String.valueOf(nameElements != null ? nameElements.size() : "null"));
 
         // initiate holder of containers for system and device structure content, for performance reasons
         HolderSystemDeviceStructure holder = new HolderSystemDeviceStructure(holderIRepositories);
@@ -757,7 +757,7 @@ public class NamesService {
             deletedNameElements.add(NameElementUtil.getNameElement(name));
         }
 
-        LOGGER.log(Level.INFO, "deleteNames, deletedNameElements.size: " + deletedNameElements.size());
+        LOGGER.log(Level.INFO, "deleteNames, deletedNameElements.size: {0}", deletedNameElements.size());
         return deletedNameElements;
     }
 
diff --git a/src/main/java/org/openepics/names/service/StructuresService.java b/src/main/java/org/openepics/names/service/StructuresService.java
index 648b86072fdbf4a4a5991f95012e4777fdea371d..e8b55d22ba19c1ecf5c006b46ea4b9d2076090c6 100644
--- a/src/main/java/org/openepics/names/service/StructuresService.java
+++ b/src/main/java/org/openepics/names/service/StructuresService.java
@@ -90,6 +90,8 @@ public class StructuresService {
 
     private static final Logger LOGGER = Logger.getLogger(StructuresService.class.getName());
 
+    private static final String SYSTEM_STRUCTURE_ONLY = "System structure only";
+
     private EssNamingConvention namingConvention;
 
     private HolderIRepositories holderIRepositories;
@@ -146,7 +148,7 @@ public class StructuresService {
         //     return
         //         structure elements for created structures
 
-        LOGGER.log(Level.INFO, "createStructures, structureElements.size:        " + String.valueOf(structureElements != null ? structureElements.size() : "null"));
+        LOGGER.log(Level.INFO, "createStructures, structureElements.size:        {0}", String.valueOf(structureElements != null ? structureElements.size() : "null"));
 
         // initiate holder of containers for system and device structure content, for performance reasons
         HolderSystemDeviceStructure holder = new HolderSystemDeviceStructure(holderIRepositories);
@@ -256,7 +258,7 @@ public class StructuresService {
             }
         }
 
-        LOGGER.log(Level.INFO, "createStructures, createdStructureElements.size: " + createdStructureElements.size());
+        LOGGER.log(Level.INFO, "createStructures, createdStructureElements.size: {0}", createdStructureElements.size());
         return createdStructureElements;
     }
 
@@ -268,36 +270,35 @@ public class StructuresService {
         return readStructures(type, statuses, deleted, queryFields, queryValues, Boolean.FALSE, orderBy, isAsc, offset, limit, StructureChoice.STRUCTURE);
     }
 
-    //need to have public static enum StructureChoice {HISTORY, STRUCTURE};
     public ResponsePageStructureElements readStructures(
             Type type, Status[] statuses, Boolean deleted, FieldStructure[] queryFields, String[] queryValues, Boolean includeHistory,
             FieldStructure orderBy, Boolean isAsc, Integer offset, Integer limit,
             StructureChoice structureChoice) {
 
-        LOGGER.log(Level.INFO, "readStructures, type:                   " + type);
-        LOGGER.log(Level.INFO, "readStructures, statuses.length:        " + String.valueOf(statuses != null ? statuses.length : "null"));
-        LOGGER.log(Level.INFO, "readStructures, deleted:                " + deleted);
-        LOGGER.log(Level.INFO, "readStructures, queryFields.length:     " + String.valueOf(queryFields != null ? queryFields.length : "null"));
-        LOGGER.log(Level.INFO, "readStructures, queryValues.length:     " + String.valueOf(queryValues != null ? queryValues.length : "null"));
-        LOGGER.log(Level.INFO, "readStructures, includeHistory:         " + includeHistory);
-        LOGGER.log(Level.INFO, "readStructures, orderBy:                " + orderBy);
-        LOGGER.log(Level.INFO, "readStructures, isAsc:                  " + isAsc);
-        LOGGER.log(Level.INFO, "readStructures, offset:                 " + offset);
-        LOGGER.log(Level.INFO, "readStructures, limit:                  " + limit);
-        LOGGER.log(Level.INFO, "readStructures, structureChoice:        " + structureChoice);
+        LOGGER.log(Level.INFO, "readStructures, type:                   {0}", type);
+        LOGGER.log(Level.INFO, "readStructures, statuses.length:        {0}", String.valueOf(statuses != null ? statuses.length : "null"));
+        LOGGER.log(Level.INFO, "readStructures, deleted:                {0}", deleted);
+        LOGGER.log(Level.INFO, "readStructures, queryFields.length:     {0}", String.valueOf(queryFields != null ? queryFields.length : "null"));
+        LOGGER.log(Level.INFO, "readStructures, queryValues.length:     {0}", String.valueOf(queryValues != null ? queryValues.length : "null"));
+        LOGGER.log(Level.INFO, "readStructures, includeHistory:         {0}", includeHistory);
+        LOGGER.log(Level.INFO, "readStructures, orderBy:                {0}", orderBy);
+        LOGGER.log(Level.INFO, "readStructures, isAsc:                  {0}", isAsc);
+        LOGGER.log(Level.INFO, "readStructures, offset:                 {0}", offset);
+        LOGGER.log(Level.INFO, "readStructures, limit:                  {0}", limit);
+        LOGGER.log(Level.INFO, "readStructures, structureChoice:        {0}", structureChoice);
         if (statuses != null && statuses.length > 0) {
             for (Status status : statuses) {
-                LOGGER.log(Level.INFO, "readStructures, status:                 " + status);
+                LOGGER.log(Level.INFO, "readStructures, status:                 {0}", status);
             }
         }
         if (queryFields != null && queryFields.length > 0) {
             for (FieldStructure queryField : queryFields) {
-                LOGGER.log(Level.INFO, "readStructures, queryField:             " + queryField);
+                LOGGER.log(Level.INFO, "readStructures, queryField:             {0}", queryField);
             }
         }
         if (queryValues != null && queryValues.length > 0) {
             for (String queryValue : queryValues) {
-                LOGGER.log(Level.INFO, "readStructures, queryValue:             " + queryValue);
+                LOGGER.log(Level.INFO, "readStructures, queryValue:             {0}", queryValue);
             }
         }
 
@@ -330,7 +331,7 @@ public class StructuresService {
                     orderBy, isAsc,
                     offset, limit);
             totalCount = holderRepositories.getSystemGroupRepository().countSystemGroups(statuses, deleted, queryFields, queryValues, includeHistory);
-            LOGGER.log(Level.INFO, "readStructures, systemGroups.size:      " + systemGroups.size());
+            LOGGER.log(Level.INFO, "readStructures, systemGroups.size:      {0}", systemGroups.size());
             structureElements.addAll(StructureElementUtil.getStructureElementsForSystemGroups(systemGroups, holder, structureChoice));
         } else if (Type.SYSTEM.equals(type)) {
             List<System> systems = holderRepositories.getSystemRepository().readSystems(
@@ -339,7 +340,7 @@ public class StructuresService {
                     orderBy, isAsc,
                     offset, limit);
             totalCount = holderRepositories.getSystemRepository().countSystems(statuses, deleted, queryFields, queryValues, includeHistory);
-            LOGGER.log(Level.INFO, "readStructures, systems.size:           " + systems.size());
+            LOGGER.log(Level.INFO, "readStructures, systems.size:           {0}", systems.size());
             structureElements.addAll(StructureElementUtil.getStructureElementsForSystems(systems, holder, structureChoice));
         } else if (Type.SUBSYSTEM.equals(type)) {
             List<Subsystem> subsystems = holderRepositories.getSubsystemRepository().readSubsystems(
@@ -348,7 +349,7 @@ public class StructuresService {
                     orderBy, isAsc,
                     offset, limit);
             totalCount = holderRepositories.getSubsystemRepository().countSubsystems(statuses, deleted, queryFields, queryValues, includeHistory);
-            LOGGER.log(Level.INFO, "readStructures, subsystems.size:        " + subsystems.size());
+            LOGGER.log(Level.INFO, "readStructures, subsystems.size:        {0}", subsystems.size());
             structureElements.addAll(StructureElementUtil.getStructureElementsForSubsystems(subsystems, holder, structureChoice));
         } else if (Type.DISCIPLINE.equals(type)) {
             List<Discipline> disciplines = holderRepositories.getDisciplineRepository().readDisciplines(
@@ -357,7 +358,7 @@ public class StructuresService {
                     orderBy, isAsc,
                     offset, limit);
             totalCount = holderRepositories.getDisciplineRepository().countDisciplines(statuses, deleted, queryFields, queryValues, includeHistory);
-            LOGGER.log(Level.INFO, "readStructures, disciplines.size:       " + disciplines.size());
+            LOGGER.log(Level.INFO, "readStructures, disciplines.size:       {0}", disciplines.size());
             structureElements.addAll(StructureElementUtil.getStructureElementsForDisciplines(disciplines, holder, structureChoice));
         } else if (Type.DEVICEGROUP.equals(type)) {
             List<DeviceGroup> deviceGroups = holderRepositories.getDeviceGroupRepository().readDeviceGroups(
@@ -366,7 +367,7 @@ public class StructuresService {
                     orderBy, isAsc,
                     offset, limit);
             totalCount = holderRepositories.getDeviceGroupRepository().countDeviceGroups(statuses, deleted, queryFields, queryValues, includeHistory);
-            LOGGER.log(Level.INFO, "readStructures, deviceGroups.size:      " + deviceGroups.size());
+            LOGGER.log(Level.INFO, "readStructures, deviceGroups.size:      {0}", deviceGroups.size());
             structureElements.addAll(StructureElementUtil.getStructureElementsForDeviceGroups(deviceGroups, holder, structureChoice));
         } else if (Type.DEVICETYPE.equals(type)) {
             List<DeviceType> deviceTypes = holderRepositories.getDeviceTypeRepository().readDeviceTypes(
@@ -375,12 +376,12 @@ public class StructuresService {
                     orderBy, isAsc,
                     offset, limit);
             totalCount = holderRepositories.getDeviceTypeRepository().countDeviceTypes(statuses, deleted, queryFields, queryValues, includeHistory);
-            LOGGER.log(Level.INFO, "readStructures, deviceTypes.size:       " + deviceTypes.size());
+            LOGGER.log(Level.INFO, "readStructures, deviceTypes.size:       {0}", deviceTypes.size());
             structureElements.addAll(StructureElementUtil.getStructureElementsForDeviceTypes(deviceTypes, holder, structureChoice));
         }
 
         ResponsePageStructureElements response = new ResponsePageStructureElements(structureElements, totalCount, structureElements.size(), offset, limit);
-        LOGGER.log(Level.INFO, "readStructures, response:           " + response);
+        LOGGER.log(Level.INFO, "readStructures, response:           {0}", response);
         return response;
     }
 
@@ -395,8 +396,8 @@ public class StructuresService {
         // return
         //     structure elements for structures
 
-        LOGGER.log(Level.INFO, "readStructuresChildren, type:                   " + type);
-        LOGGER.log(Level.INFO, "readStructuresChildren, uuid:                   " + uuid);
+        LOGGER.log(Level.INFO, "readStructuresChildren, type:                   {0}", type);
+        LOGGER.log(Level.INFO, "readStructuresChildren, uuid:                   {0}", uuid);
 
         // validate input
         ValidateUtil.validateInputType(type);
@@ -838,7 +839,7 @@ public class StructuresService {
         //     return
         //         structure elements for updated structures
 
-        LOGGER.log(Level.INFO, "updateStructures, structureElements.size:        " + String.valueOf(structureElements != null ? structureElements.size() : "null"));
+        LOGGER.log(Level.INFO, "updateStructures, structureElements.size:        {0}", String.valueOf(structureElements != null ? structureElements.size() : "null"));
 
         // initiate holder of containers for system and device structure content, for performance reasons
         HolderSystemDeviceStructure holder = new HolderSystemDeviceStructure(holderIRepositories);
@@ -948,7 +949,7 @@ public class StructuresService {
             }
         }
 
-        LOGGER.log(Level.INFO, "updateStructures, updatedStructureElements.size: " + updatedStructureElements.size());
+        LOGGER.log(Level.INFO, "updateStructures, updatedStructureElements.size: {0}", updatedStructureElements.size());
         return updatedStructureElements;
     }
 
@@ -968,7 +969,7 @@ public class StructuresService {
         //         structure elements for deleted structures
         // TODO continue ---> validation error
 
-        LOGGER.log(Level.INFO, "deleteStructures, structureElements.size:        " + String.valueOf(structureElements != null ? structureElements.size() : "null"));
+        LOGGER.log(Level.INFO, "deleteStructures, structureElements.size:        {0}", String.valueOf(structureElements != null ? structureElements.size() : "null"));
 
         // initiate holder of containers for system and device structure content, for performance reasons
         HolderSystemDeviceStructure holder = new HolderSystemDeviceStructure(holderIRepositories);
@@ -1112,7 +1113,7 @@ public class StructuresService {
             }
         }
 
-        LOGGER.log(Level.INFO, "deleteStructures, deletedStructureElements.size: " + deletedStructureElements.size());
+        LOGGER.log(Level.INFO, "deleteStructures, deletedStructureElements.size: {0}", deletedStructureElements.size());
         return deletedStructureElements;
     }
 
@@ -1129,7 +1130,7 @@ public class StructuresService {
         //         updated structure element
         // TODO continue ---> validation error
 
-        LOGGER.log(Level.INFO, "approveStructures, structureElements.size:         " + String.valueOf(structureElements != null ? structureElements.size() : "null"));
+        LOGGER.log(Level.INFO, "approveStructures, structureElements.size:         {0}", String.valueOf(structureElements != null ? structureElements.size() : "null"));
 
         // initiate holder of containers for system and device structure content, for performance reasons
         HolderSystemDeviceStructure holder = new HolderSystemDeviceStructure(holderIRepositories);
@@ -1178,9 +1179,9 @@ public class StructuresService {
                 // automatically create name when system structure is approved (after create)
                 // create name within current transaction
                 if (!StringUtils.isEmpty(systemGroup.getMnemonic())) {
-                    NameElementCommand nameElement = new NameElementCommand(null, systemGroup.getUuid(), null, null, "System structure only", null);
+                    NameElementCommand nameElement = new NameElementCommand(null, systemGroup.getUuid(), null, null, SYSTEM_STRUCTURE_ONLY, null);
                     NameElement createdNameElement = namesService.createName(nameElement, holder, processedBy);
-                    LOGGER.log(Level.INFO, "approveStructures, nameElement created, name:      " + createdNameElement.getName());
+                    LOGGER.log(Level.INFO, "approveStructures, nameElement created, name:      {0}", createdNameElement.getName());
                 }
 
                 // add
@@ -1214,9 +1215,9 @@ public class StructuresService {
                 // automatically create name when system structure is approved (after create)
                 // create name within current transaction
                 if (!StringUtils.isEmpty(system.getMnemonic())) {
-                    NameElementCommand nameElement = new NameElementCommand(null, system.getUuid(), null, null, "System structure only", null);
+                    NameElementCommand nameElement = new NameElementCommand(null, system.getUuid(), null, null, SYSTEM_STRUCTURE_ONLY, null);
                     NameElement createdNameElement = namesService.createName(nameElement, holder, processedBy);
-                    LOGGER.log(Level.INFO, "approveStructures, nameElement created, name:      " + createdNameElement.getName());
+                    LOGGER.log(Level.INFO, "approveStructures, nameElement created, name:      {0}", createdNameElement.getName());
                 }
 
                 // add
@@ -1250,9 +1251,9 @@ public class StructuresService {
                 // automatically create name when system structure is approved (after create)
                 // create name within current transaction
                 if (!StringUtils.isEmpty(subsystem.getMnemonic())) {
-                    NameElementCommand nameElement = new NameElementCommand(null, subsystem.getUuid(), null, null, "System structure only", null);
+                    NameElementCommand nameElement = new NameElementCommand(null, subsystem.getUuid(), null, null, SYSTEM_STRUCTURE_ONLY, null);
                     NameElement createdNameElement = namesService.createName(nameElement, holder, processedBy);
-                    LOGGER.log(Level.INFO, "approveStructures, nameElement created, name:      " + createdNameElement.getName());
+                    LOGGER.log(Level.INFO, "approveStructures, nameElement created, name:      {0}", createdNameElement.getName());
                 }
 
                 // add
@@ -1343,7 +1344,7 @@ public class StructuresService {
             }
         }
 
-        LOGGER.log(Level.INFO, "approveStructures, approvedStructureElements.size: " + approvedStructureElements.size());
+        LOGGER.log(Level.INFO, "approveStructures, approvedStructureElements.size: {0}", approvedStructureElements.size());
         return approvedStructureElements;
     }
 
@@ -1358,7 +1359,7 @@ public class StructuresService {
         //         updated structure element
         // TODO continue ---> validation error
 
-        LOGGER.log(Level.INFO, "cancelStructures, structureElements.size:          " + String.valueOf(structureElements != null ? structureElements.size() : "null"));
+        LOGGER.log(Level.INFO, "cancelStructures, structureElements.size:          {0}", String.valueOf(structureElements != null ? structureElements.size() : "null"));
 
         // initiate holder of containers for system and device structure content, for performance reasons
         HolderSystemDeviceStructure holder = new HolderSystemDeviceStructure(holderIRepositories);
@@ -1465,7 +1466,7 @@ public class StructuresService {
             }
         }
 
-        LOGGER.log(Level.INFO, "cancelStructures, cancelledStructureElements.size: " + cancelledStructureElements.size());
+        LOGGER.log(Level.INFO, "cancelStructures, cancelledStructureElements.size: {0}", cancelledStructureElements.size());
         return cancelledStructureElements;
     }
 
@@ -1480,7 +1481,7 @@ public class StructuresService {
         //         updated structure element
         // TODO continue ---> validation error
 
-        LOGGER.log(Level.INFO, "rejectStructures, structureElements.size:         " + String.valueOf(structureElements != null ? structureElements.size() : "null"));
+        LOGGER.log(Level.INFO, "rejectStructures, structureElements.size:         {0}", String.valueOf(structureElements != null ? structureElements.size() : "null"));
 
         // initiate holder of containers for system and device structure content, for performance reasons
         HolderSystemDeviceStructure holder = new HolderSystemDeviceStructure(holderIRepositories);
@@ -1587,7 +1588,7 @@ public class StructuresService {
             }
         }
 
-        LOGGER.log(Level.INFO, "rejectStructures, rejectedStructureElements.size: " + rejectedStructureElements.size());
+        LOGGER.log(Level.INFO, "rejectStructures, rejectedStructureElements.size: {0}", rejectedStructureElements.size());
         return rejectedStructureElements;
     }
 
diff --git a/src/main/java/org/openepics/names/util/ExcelUtil.java b/src/main/java/org/openepics/names/util/ExcelUtil.java
index 69dabc0a4f321586bcf7f36b1f47527d0f235bc1..e7f72859f6c6c2ff267769a365da7abd0e240bb8 100644
--- a/src/main/java/org/openepics/names/util/ExcelUtil.java
+++ b/src/main/java/org/openepics/names/util/ExcelUtil.java
@@ -70,10 +70,10 @@ public class ExcelUtil {
 
     // width (in units of 1/256th of a character width)
     // column width 2.75 inch (to fit header text and uuid)
-    public static final int        SHEET_COLUMN_WIDTH              = 28 * 256 + 64;
+    private static final int        SHEET_COLUMN_WIDTH              = 28 * 256 + 64;
 
-    public static final int        NAMEELEMENTCOMMAND_LENGTH       = 6;
-    public static final String[][] NAMEELEMENT_HEADER_COMMENT      = {
+    private static final int        NAMEELEMENTCOMMAND_LENGTH       = 6;
+    private static final String[][] NAMEELEMENT_HEADER_COMMENT      = {
             {"Uuid",                  "Identity (uuid) of the name entry. Value is created server-side."},
             {"Parentsystemstructure", "Identity (uuid) for the system structure parent."},
             {"Parentdevicestructure", "Identity (uuid) for the device structure parent (if the name entry refers to device structure)."},
@@ -90,8 +90,8 @@ public class ExcelUtil {
             {"When",                  "Date and time when the name entry was created."},
             {"Who",                   "Name (user) of who created the name entry."} };
 
-    public static final int        STRUCTUREELEMENTCOMMAND_LENGTH  = 7;
-    public static final String[][] STRUCTUREELEMENT_HEADER_COMMENT = {
+    private static final int        STRUCTUREELEMENTCOMMAND_LENGTH  = 7;
+    private static final String[][] STRUCTUREELEMENT_HEADER_COMMENT = {
             {"Uuid",                  "Identity (uuid) of the structure entry. Value is created server-side."},
             {"Type",                  "Type of the structure entry."},
             {"Parent",                "Identity (uuid) for the structure entry parent (if the structure entry has a parent)."},