If you are using EJB 2.0 and XDoclet 1.2.3 in Eclipse IDE then problem might be the EJBSession implemented methods in the class HelloBean.
Please remove all the implemented methods expect the constructor. i.e from the line number the XDoclet is throwing exceptions.
I tried this and worked fine for me.
Please let me know whether it worked for you or not and if you have already resolved the problem please share it so that I can also try that method.
Today I handled some legacy code and I got the same stack trace as mentioned above.
The solution was to disable Eclipse Save-actions. Concrete, in my Eclipse configuration the Save-actions add missing Override-annotations. These annotations seem to be unparseable for XDoclet and cause the shown exception.
Maybe this hint saves someone else a lot of debugging time.