PnC-Adventures using Java / easily moddable / open source

[michael_kuerbis]

I have an idea for a mod in a point and click adventure game. What I need is a game to test it on.
The content of the game does not matter. But it should be a point and click adventure, not a hidden object game.
I am looking for a game this is easy to modify. My intention is directed towards the gameplay, the scripting and the controls.

Properties of easily moddable games:

• Written in Java (at least the gameplay engine) - Java is fairly easy to reverse engineer
  
• Known mods - the game has been proven to be moddable
  
• Open Source - such a game would obviously be easy to mod

Dismissed ideas:

• Edna and Harvey: The Breakout uses Java and I have taken a look at it, but my modding idea cannot be implemented with that game.
  
• SCUMMVM: Many adventures could be played using SCUMMVM, but that is far too complicated for my ambitions.

The game does not necessarily need to be available on Steam, but it must be available for PC.
If the game is already in my library, tell me anyway. I have lost track.

So any suggestions?