DejaVu

The execution behavior of a Java application can be non-deterministic due to multithreading. This non-determinism makes understanding and debugging multithreaded Java applications a difficult and laborious process. DejaVu (Deterministic Java Replay Utility) helps the user in understanding and debugging non-deterministic Java applications by deterministically replaying the execution behavior of a non-deterministic execution. In this demo, we will present a debugger for the Jalapeño Java Virtual Machine that utilizes the replay capability provided by DejaVu. The debugger helps in isolating non-deterministic failure(s) by faithfully reproducing the same execution behavior that led to the observe failure(s). Jalapeno is a JVM being developed at IBM T. J. Watson Research Center. The debugger provides the following features: (1) DejaVu deterministically replays Java programs; (2) Remote Reflection supports general debugging functionalities such as setting breakpoints, examining the program state, and detecting deadlocks; and (3) a GUI provides an intuitive and easy to use interface.