The poster is asking how to find/ween the memory allocation hog in his 250,000 lines of code.

I have not used the profiler yet but it is integrated into the Netbeans IDE which is free.
http://profiler.netbeans.org/

There are other profilers, just google for java profilers. You can also set higher heap sizes for the jvm with command line switches for java.exe but this won't solve memory hog issues.