NoSuchMethodError message

I installed the new JDK, but when I attempt to run an app I get the following error message:

Exception in thread "main" java.lang.NoSuchMethodError: main

Could someone tell me what is wrong? What is this error message trying to tell me and how do I get an app to run? I get this when I try to run the simple hello world tutorial app, or any other app for that matter.

[386 byte] By [Markenrodea] at [2007-9-28 2:36:47]