diff --git a/YACOSCore/ejbModule/org/yacos/core/users/User.java b/YACOSCore/ejbModule/org/yacos/core/users/User.java
index ea9ed9d..f97a3ea 100644
--- a/YACOSCore/ejbModule/org/yacos/core/users/User.java
+++ b/YACOSCore/ejbModule/org/yacos/core/users/User.java
@@ -1,7 +1,8 @@
 package org.yacos.core.users;
 
-import java.util.ArrayList;
+import java.io.Serializable;
 import java.util.Collection;
+
 import javax.persistence.Entity;
 import javax.persistence.Id;
 import javax.persistence.OneToMany;
@@ -17,7 +18,7 @@ import org.yacos.core.conferences.Conference;
  *
  */
 @Entity
-public class User {
+public class User implements Serializable{
 	/**
 	 * Unique login of the user
 	 * Is used to identify the user, should be unique and can't be modified