I found a Bug in Seam and It's not fixed in the Version 2. If the MockFacesContext was created by the ExceptionFilter in the "endWebRequestAfterException" method this faces context is still there after the call FacesContext.getCurrentInstance().release(). If another WebApplication gets this "unclean" thread and ask for a FacesContext he gets the wrong context and the application may crash. Please implement in the MockFacesContext the release method as follow: @Override public void release() { setCurrentInstance(null); } Thanks Alex View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4095643#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...