diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/context/SecurityContextMapper.java b/src/main/java/org/gcube/informationsystem/resourceregistry/context/SecurityContextMapper.java
index 09ed7b8..4fcf8e7 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/context/SecurityContextMapper.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/context/SecurityContextMapper.java
@@ -86,7 +86,7 @@ public abstract class SecurityContextMapper {
 		}
 	}
 
-	public enum SecurityType {
+	public static enum SecurityType {
 		ROLE("Role"), USER("User");
 
 		private final String name;
@@ -100,7 +100,7 @@ public abstract class SecurityContextMapper {
 		}
 	}
 
-	public enum PermissionMode {
+	public static enum PermissionMode {
 		READER("Reader"), WRITER("Writer");
 
 		private final String name;