diff --git a/src/main/java/de/thm/arsnova/services/SessionService.java b/src/main/java/de/thm/arsnova/services/SessionService.java
index f5f8190afc3e13cb596d7770febec9cc0512a8a8..7a1b6538c60f8285ed57856bfe66ed8abf9c9e6f 100644
--- a/src/main/java/de/thm/arsnova/services/SessionService.java
+++ b/src/main/java/de/thm/arsnova/services/SessionService.java
@@ -19,6 +19,7 @@
 
 package de.thm.arsnova.services;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -88,7 +89,7 @@ public class SessionService implements ISessionService {
 			allAvailableSessions.put(session.get_id(), session);
 		}
 		
-		return (List<Session>) allAvailableSessions.values();
+		return new ArrayList<Session>(allAvailableSessions.values());
 	}
 	
 	@Override