StackOverflowError Stack size too small. Use java -Xss to increase default stacksize.

These usually happen when you have recursion, a method that calls itself, perhaps indirectly via a second method. You have simply nested to deeply. Another source of the problem is calling method x() or this.x() when you meant to call super. x(), usually when inside method x. If you legitimately overflowed the stack, you may rescue yourself by getting the runtime to allocate more memory for the stack for each thread with java.exe -Xss128