java.lang.RuntimeException: Uncompilable source code - what can cause this?

Question

This error is just bizarre, my code compiles fine, I can see there are no problems with it, yet this error has just popped up. I have tried re-starting NetBeans and there is

Answer 1

I guess you are using an IDE (like Netbeans) which allows you to run the code even if certain classes are not compilable. During the application's runtime, if you access this class it would lead to this exception.