java.util.ConcurrentModificationException with NiftyGUI


I have a problem with NiftyGUI and screencontrollers. When I call a method from my screencontroller to the main class I get this error:

28-dec-2010 22:13:37 handleError

SEVERE: Uncaught exception thrown in Thread[LWJGL Renderer Thread,5,main]


at java.util.AbstractList$Itr.checkForComodification(

at java.util.AbstractList$

at com.jme3.renderer.RenderManager.renderViewPort(

at com.jme3.renderer.RenderManager.render(

at cargame.core.CarGame.update(

at com.jme3.system.lwjgl.LwjglAbstractDisplay.runLoop(

at com.jme3.system.lwjgl.LwjglDisplay.runLoop(



Should I implement my screencontroller in a seperate class or in the appstate ? Is there an example how to implement a screencontroller ?

Thanks in advance.

It looks like this topic is about the same issue:

Edit: It works now. See the above link.