Hi,

One of the exceptions I always find hard to track is:

sys::ArgErr: java.lang.IllegalArgumentException: Comparison method violates its general contract! 

Usually, it is thrown without any kind of details regarding the file throwing the error or the line or the method name. Can someone give me a hint on How can I find that?

Wow - I've never seen that!

But it's a Java exception, not a Fantom one. A quick google gives me:

Java error: Comparison method violates its general contract

It seems to mean that your comparison method doesn't do what it's supposed to do.

Note there's also an answer that states the exception is specific to JREs > 1.6.

Um, if I wasn't clear, the error is probably in a Obj.compare() or List.sort() method.

Are you sure there's nothing else in the stack trace?

Nope, no stacktraces.

I understand the problem, I previously managed to fix things by guessing, but I was wondering if I could somehow get the stacktrace so I can be sure where exactly does the error happen.

If the code is not too big can you post it or a link to it. I want to try it out myself

Unfortunately the code is big and belongs to my employer so I can't share it but I will try to make a test case showing the error if possible.

That exception means you have a bug in a compare() method where you don't consistently order your objects. It typically always happens during a sort operation and is raised by the underlying Java sorting library