WhizCoder is online IDE with compiler, interpreter and debugger. Supported programming languages are Java and Python. Available debuggers are JDB for Java and PDB for Python. Code and Debug on WhizCoder and unlish great coder within you.
C. Bolz, A. Cuni, M. Fijalkowski, and A. Rigo. Proceedings of the 4th Workshop on the Implementation, Compilation, Optimization of Object-Oriented Languages and Programming Systems, page 18--25. ACM, (2009)