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Is that the same variable your loop is checking against? Are you sure?

Without an SSCCE I'm only guessing, but you're either using two different variables with the same name, or you're dealing...

So what happens when you put a println in the stop() method? Does it properly set the boolean to false?

Okay, so when do you expect it to exit that? What happens instead?

Recommended reading: http://www.javaprogrammingforums.com/blogs/copeg/5-debugging-system-out-println.html

When posting code, please use code tags, and preferably boil your problem down to an SSCCE that we can copy and paste to see the issue.

Why are you doing your painting like that? Recommended...