Abstract Method Error

Question

I am working on a project in netbeans that when I launch it using the glassfish 3.1.2.Everything works fine.But when i call the /invite url which is mapped to following meth

Answer 1

Put a Breakpoint on the Exception (or the line where it is occurring) to find out which class/method exactly is causing the problem, then search your classpath for all occurrences of this class. If you have more than one version of a class on your classpath, remove the wrong one.