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

I also had the same issue in my case the problem was i have two .class files with same name in two different jar files.I excluded on of the jar file from pom.xml it started working!