If you defined an EJB with@

@Startup
@Singleton
public class ModuleMain implements Runnable { ...

This triggers a SecurityException: Prohibitied package name: java.lang

during the deploy and fails to deploy.

If you change it to "implements SomeUserDefinedInterface" it deploys ok.
If you change it to "implements Runnable,SomeUserDefinedInterface" it deploys ok.

I will attach JBoss AS7 log output during the deploy and also a Maven project you can build a working testcase from.

In this project you should take a look at the class ModuleMain.java I have included the log output in there as well as some notes on the minimum change needed to workaround the problem or try other scenarios related (i.e. modifying only the declared implements interface list for the class ModuleMain)

I have marked bug with EJB module as this is an EJB deployment issue I'm sure that module owner can reassign if it is the wrong component.