I'm hoping I can clarify this issue.
Note, a similar question has been asked here, but it doesn't really give a specific enough answer that I can comprehend at this point! :- How does one escape the GPL?
I plan to use a game engine that has been released under GPL to develop a MMOG, and I plan to distribute the client for free. I'm concerned that when it comes time to release my game, I'm going to have to release the entire source code under GPL, which opens my game to risk of abuse, where someone can learn how to potentially hack my game client and give them an unfair advantage etc.
If I understand GPL, I only need to distribute code that I've edited directly. In the case of Java, I can extend the available classes, do to what I need them to do, rather than go back and make edits in the classes themselves. If i'm using the original code in this way, do I just need to point out that the code is available from the engine developers
Does extending a class constitute 'editing the source?'