diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERAlreadyPresentException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/AlreadyPresentException.java
similarity index 56%
rename from src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERAlreadyPresentException.java
rename to src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/AlreadyPresentException.java
index 3ecb7ce..7ae141c 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERAlreadyPresentException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/AlreadyPresentException.java
@@ -4,22 +4,22 @@ package org.gcube.informationsystem.resourceregistry.api.exceptions;
  * @author Luca Frosini (ISTI - CNR)
  * 
  */
-public class ERAlreadyPresentException extends ERException {
+public class AlreadyPresentException extends ResourceRegistryException {
 
 	/**
 	 * Generated Serial Version UID
 	 */
 	private static final long serialVersionUID = 1129094888903457750L;
 
-	public ERAlreadyPresentException(String message) {
+	public AlreadyPresentException(String message) {
 		super(message);
 	}
 	
-	public ERAlreadyPresentException(Throwable cause) {
+	public AlreadyPresentException(Throwable cause) {
 		super(cause);
 	}
 	
-	public ERAlreadyPresentException(String message, Throwable cause) {
+	public AlreadyPresentException(String message, Throwable cause) {
 		super(message, cause);
 	}
 
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERAvailableInAnotherContextException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/AvailableInAnotherContextException.java
similarity index 51%
rename from src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERAvailableInAnotherContextException.java
rename to src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/AvailableInAnotherContextException.java
index 95aea8e..bd87900 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERAvailableInAnotherContextException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/AvailableInAnotherContextException.java
@@ -4,22 +4,22 @@ package org.gcube.informationsystem.resourceregistry.api.exceptions;
  * @author Luca Frosini (ISTI - CNR)
  * 
  */
-public class ERAvailableInAnotherContextException extends ERException {
+public class AvailableInAnotherContextException extends ResourceRegistryException {
 
 	/**
 	 * Generated Serial Version UID
 	 */
 	private static final long serialVersionUID = -7499131763751652582L;
 
-	public ERAvailableInAnotherContextException(String message) {
+	public AvailableInAnotherContextException(String message) {
 		super(message);
 	}
 	
-	public ERAvailableInAnotherContextException(Throwable cause) {
+	public AvailableInAnotherContextException(Throwable cause) {
 		super(cause);
 	}
 	
-	public ERAvailableInAnotherContextException(String message, Throwable cause) {
+	public AvailableInAnotherContextException(String message, Throwable cause) {
 		super(message, cause);
 	}
 
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERCreationException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/CreationException.java
similarity index 58%
rename from src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERCreationException.java
rename to src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/CreationException.java
index cf91e4d..a7cc3db 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERCreationException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/CreationException.java
@@ -4,22 +4,22 @@ package org.gcube.informationsystem.resourceregistry.api.exceptions;
  * @author Luca Frosini (ISTI - CNR)
  * 
  */
-public class ERCreationException extends ERException {
+public class CreationException extends ResourceRegistryException {
 
 	/**
 	 * Generated Serial Version UID
 	 */
 	private static final long serialVersionUID = -6223557776095431118L;
 
-	public ERCreationException(String message) {
+	public CreationException(String message) {
 		super(message);
 	}
 
-	public ERCreationException(Throwable cause) {
+	public CreationException(Throwable cause) {
 		super(cause);
 	}
 	
-	public ERCreationException(String message, Throwable cause) {
+	public CreationException(String message, Throwable cause) {
 		super(message, cause);
 	}
 }
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERException.java
deleted file mode 100644
index b94124b..0000000
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERException.java
+++ /dev/null
@@ -1,29 +0,0 @@
-/**
- * 
- */
-package org.gcube.informationsystem.resourceregistry.api.exceptions;
-
-/**
- * @author Luca Frosini (ISTI - CNR)
- *
- */
-public class ERException extends ResourceRegistryException {
-
-	/**
-	 * Generated Serial Version UID
-	 */
-	private static final long serialVersionUID = -2231802464980906972L;
-
-	public ERException(String message) {
-		super(message);
-	}
-	
-	public ERException(Throwable cause) {
-		super(cause);
-	}
-	
-	public ERException(String message, Throwable cause) {
-		super(message, cause);
-	}
-	
-}
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERNotFoundException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/NotFoundException.java
similarity index 58%
rename from src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERNotFoundException.java
rename to src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/NotFoundException.java
index 9182b92..dc955a7 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/ERNotFoundException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/NotFoundException.java
@@ -4,22 +4,22 @@ package org.gcube.informationsystem.resourceregistry.api.exceptions;
  * @author Luca Frosini (ISTI - CNR)
  * 
  */
-public class ERNotFoundException extends ERException {
+public class NotFoundException extends ResourceRegistryException {
 
 	/**
 	 * Generated Serial Version UID
 	 */
 	private static final long serialVersionUID = -1687373446724146351L;
 
-	public ERNotFoundException(String message) {
+	public NotFoundException(String message) {
 		super(message);
 	}
 
-	public ERNotFoundException(Throwable cause) {
+	public NotFoundException(Throwable cause) {
 		super(cause);
 	}
 	
-	public ERNotFoundException(String message, Throwable cause) {
+	public NotFoundException(String message, Throwable cause) {
 		super(message, cause);
 	}
 }
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/context/ContextAlreadyPresentException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/context/ContextAlreadyPresentException.java
index b44c11b..baa247f 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/context/ContextAlreadyPresentException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/context/ContextAlreadyPresentException.java
@@ -1,9 +1,11 @@
 package org.gcube.informationsystem.resourceregistry.api.exceptions.context;
 
+import org.gcube.informationsystem.resourceregistry.api.exceptions.AlreadyPresentException;
+
 /**
  * @author Luca Frosini (ISTI - CNR)
  */
-public class ContextAlreadyPresentException extends ContextException {
+public class ContextAlreadyPresentException extends AlreadyPresentException {
 
 	/**
 	 * Generated Serial Version UID
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/context/ContextNotFoundException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/context/ContextNotFoundException.java
index dc0bde4..63df47c 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/context/ContextNotFoundException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/context/ContextNotFoundException.java
@@ -1,10 +1,12 @@
 package org.gcube.informationsystem.resourceregistry.api.exceptions.context;
 
+import org.gcube.informationsystem.resourceregistry.api.exceptions.NotFoundException;
+
 /**
  * @author Luca Frosini (ISTI - CNR)
  * 
  */
-public class ContextNotFoundException extends ContextException {
+public class ContextNotFoundException extends NotFoundException {
 
 	/**
 	 * Generated Serial Version UID
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityAlreadyPresentException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityAlreadyPresentException.java
index ad55169..f44a4cc 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityAlreadyPresentException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityAlreadyPresentException.java
@@ -1,12 +1,12 @@
 package org.gcube.informationsystem.resourceregistry.api.exceptions.entity;
 
-import org.gcube.informationsystem.resourceregistry.api.exceptions.ERAlreadyPresentException;
+import org.gcube.informationsystem.resourceregistry.api.exceptions.AlreadyPresentException;
 
 /**
  * @author Luca Frosini (ISTI - CNR)
  * 
  */
-public class EntityAlreadyPresentException extends ERAlreadyPresentException {
+public class EntityAlreadyPresentException extends AlreadyPresentException {
 
 	/**
 	 * Generated Serial Version UID
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityAvailableInAnotherContextException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityAvailableInAnotherContextException.java
index 0c7ac75..e498070 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityAvailableInAnotherContextException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityAvailableInAnotherContextException.java
@@ -1,11 +1,11 @@
 package org.gcube.informationsystem.resourceregistry.api.exceptions.entity;
 
-import org.gcube.informationsystem.resourceregistry.api.exceptions.ERAvailableInAnotherContextException;
+import org.gcube.informationsystem.resourceregistry.api.exceptions.AvailableInAnotherContextException;
 
 /**
  * @author Luca Frosini (ISTI - CNR)
  */
-public class EntityAvailableInAnotherContextException extends ERAvailableInAnotherContextException {
+public class EntityAvailableInAnotherContextException extends AvailableInAnotherContextException {
 
 	/**
 	 * Generated Serial Version UID
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityCreationException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityCreationException.java
index 3d394ea..062d16f 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityCreationException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityCreationException.java
@@ -1,12 +1,12 @@
 package org.gcube.informationsystem.resourceregistry.api.exceptions.entity;
 
-import org.gcube.informationsystem.resourceregistry.api.exceptions.ERCreationException;
+import org.gcube.informationsystem.resourceregistry.api.exceptions.CreationException;
 
 /**
  * @author Luca Frosini (ISTI - CNR)
  * 
  */
-public class EntityCreationException extends ERCreationException {
+public class EntityCreationException extends CreationException {
 
 	/**
 	 * Generated Serial Version UID
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityNotFoundException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityNotFoundException.java
index 229c302..c70ee02 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityNotFoundException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/entity/EntityNotFoundException.java
@@ -1,12 +1,12 @@
 package org.gcube.informationsystem.resourceregistry.api.exceptions.entity;
 
-import org.gcube.informationsystem.resourceregistry.api.exceptions.ERNotFoundException;
+import org.gcube.informationsystem.resourceregistry.api.exceptions.NotFoundException;
 
 /**
  * @author Luca Frosini (ISTI - CNR)
  * 
  */
-public class EntityNotFoundException extends ERNotFoundException {
+public class EntityNotFoundException extends NotFoundException {
 
 	/**
 	 * Generated Serial Version UID
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationAlreadyPresentException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationAlreadyPresentException.java
index 50051cf..5b001a5 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationAlreadyPresentException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationAlreadyPresentException.java
@@ -1,11 +1,11 @@
 package org.gcube.informationsystem.resourceregistry.api.exceptions.relation;
 
-import org.gcube.informationsystem.resourceregistry.api.exceptions.ERAlreadyPresentException;
+import org.gcube.informationsystem.resourceregistry.api.exceptions.AlreadyPresentException;
 
 /**
  * @author Luca Frosini (ISTI - CNR)
  */
-public class RelationAlreadyPresentException extends ERAlreadyPresentException {
+public class RelationAlreadyPresentException extends AlreadyPresentException {
 
 	/**
 	 * Generated Serial Version UID
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationAvailableInAnotherContextException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationAvailableInAnotherContextException.java
index c1dbd6d..116ef8a 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationAvailableInAnotherContextException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationAvailableInAnotherContextException.java
@@ -1,11 +1,11 @@
 package org.gcube.informationsystem.resourceregistry.api.exceptions.relation;
 
-import org.gcube.informationsystem.resourceregistry.api.exceptions.ERAvailableInAnotherContextException;
+import org.gcube.informationsystem.resourceregistry.api.exceptions.AvailableInAnotherContextException;
 
 /**
  * @author Luca Frosini (ISTI - CNR)
  */
-public class RelationAvailableInAnotherContextException extends ERAvailableInAnotherContextException {
+public class RelationAvailableInAnotherContextException extends AvailableInAnotherContextException {
 
 	/**
 	 * Generated Serial Version UID
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationCreationException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationCreationException.java
index f3d0302..7a8b756 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationCreationException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationCreationException.java
@@ -1,12 +1,12 @@
 package org.gcube.informationsystem.resourceregistry.api.exceptions.relation;
 
-import org.gcube.informationsystem.resourceregistry.api.exceptions.ERCreationException;
+import org.gcube.informationsystem.resourceregistry.api.exceptions.CreationException;
 
 /**
  * @author Luca Frosini (ISTI - CNR)
  * 
  */
-public class RelationCreationException extends ERCreationException {
+public class RelationCreationException extends CreationException {
 
 	/**
 	 * Generated Serial Version UID
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationNotFoundException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationNotFoundException.java
index 519c929..ba6364f 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationNotFoundException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/RelationNotFoundException.java
@@ -1,11 +1,11 @@
 package org.gcube.informationsystem.resourceregistry.api.exceptions.relation;
 
-import org.gcube.informationsystem.resourceregistry.api.exceptions.ERNotFoundException;
+import org.gcube.informationsystem.resourceregistry.api.exceptions.NotFoundException;
 
 /**
  * @author Luca Frosini (ISTI - CNR)
  */
-public class RelationNotFoundException extends ERNotFoundException {
+public class RelationNotFoundException extends NotFoundException {
 
 	/**
 	 * Generated Serial Version UID
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/isparentof/IsParentOfAlreadyPresentException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/isparentof/IsParentOfAlreadyPresentException.java
index 0686867..37d1e46 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/isparentof/IsParentOfAlreadyPresentException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/isparentof/IsParentOfAlreadyPresentException.java
@@ -1,9 +1,11 @@
 package org.gcube.informationsystem.resourceregistry.api.exceptions.relation.isparentof;
 
+import org.gcube.informationsystem.resourceregistry.api.exceptions.relation.RelationAlreadyPresentException;
+
 /**
  * @author Luca Frosini (ISTI - CNR)
  */
-public class IsParentOfAlreadyPresentException extends IsParentOfException {
+public class IsParentOfAlreadyPresentException extends RelationAlreadyPresentException {
 
 	/**
 	 * Generated Serial Version UID
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/isparentof/IsParentOfNotFoundException.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/isparentof/IsParentOfNotFoundException.java
index 28fee7a..f520e64 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/isparentof/IsParentOfNotFoundException.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/exceptions/relation/isparentof/IsParentOfNotFoundException.java
@@ -1,9 +1,11 @@
 package org.gcube.informationsystem.resourceregistry.api.exceptions.relation.isparentof;
 
+import org.gcube.informationsystem.resourceregistry.api.exceptions.relation.RelationNotFoundException;
+
 /**
  * @author Luca Frosini (ISTI - CNR)
  */
-public class IsParentOfNotFoundException extends IsParentOfException {
+public class IsParentOfNotFoundException extends RelationNotFoundException {
 
 	/**
 	 * Generated Serial Version UID
diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/api/rest/httputils/HTTPCall.java b/src/main/java/org/gcube/informationsystem/resourceregistry/api/rest/httputils/HTTPCall.java
index 87791b8..de906b8 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/api/rest/httputils/HTTPCall.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/api/rest/httputils/HTTPCall.java
@@ -20,8 +20,8 @@ import org.gcube.informationsystem.model.ISManageable;
 import org.gcube.informationsystem.model.entity.Facet;
 import org.gcube.informationsystem.model.entity.Resource;
 import org.gcube.informationsystem.model.relation.Relation;
-import org.gcube.informationsystem.resourceregistry.api.exceptions.ERAvailableInAnotherContextException;
-import org.gcube.informationsystem.resourceregistry.api.exceptions.ERNotFoundException;
+import org.gcube.informationsystem.resourceregistry.api.exceptions.AvailableInAnotherContextException;
+import org.gcube.informationsystem.resourceregistry.api.exceptions.NotFoundException;
 import org.gcube.informationsystem.resourceregistry.api.exceptions.ExceptionMapper;
 import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
 import org.gcube.informationsystem.resourceregistry.api.exceptions.entity.facet.FacetAvailableInAnotherContextException;
@@ -181,8 +181,8 @@ public class HTTPCall {
 		return result;
 	}
 
-	protected <C> ERNotFoundException getElementNotFoundException(Class<C> clz)
-			throws ERNotFoundException, ResourceRegistryException {
+	protected <C> NotFoundException getElementNotFoundException(Class<C> clz)
+			throws NotFoundException, ResourceRegistryException {
 		String error = String.format("Requested %s instance was not found", clz.getSimpleName());
 		if (Resource.class.isAssignableFrom(clz)) {
 			return new ResourceNotFoundException(error);
@@ -191,10 +191,10 @@ public class HTTPCall {
 		} else if (Relation.class.isAssignableFrom(clz)) {
 			return new RelationNotFoundException(error);
 		}
-		return new ERNotFoundException(error);
+		return new NotFoundException(error);
 	}
 
-	protected <C> ERAvailableInAnotherContextException getElementAvailableInAnotherContextException(Class<C> clz) {
+	protected <C> AvailableInAnotherContextException getElementAvailableInAnotherContextException(Class<C> clz) {
 		String error = String.format("Requested %s instance was not found", clz.getSimpleName());
 		if (Resource.class.isAssignableFrom(clz)) {
 			return new ResourceAvailableInAnotherContextException(error);
@@ -203,7 +203,7 @@ public class HTTPCall {
 		} else if (Relation.class.isAssignableFrom(clz)) {
 			return new RelationAvailableInAnotherContextException(error);
 		}
-		return new ERAvailableInAnotherContextException(error);
+		return new AvailableInAnotherContextException(error);
 	}
 
 	public <C> C call(Class<C> clz, String path, HTTPMETHOD method) throws Exception {