Not an actual debugger, but this tool can record Java applications (unit tests or full-blown applications) while they run, and then you can explore visually wha

Not an actual debugger, but this tool can record Java applications (unit tests or full-blown applications) while they run, and then you can explore visually what happened through a web interface: http://findtheflow.io http://findtheflow.io. It's similar to rr because you can go back and forth in time, but unlike rr it doesn't record much of the state (besides return values) and instead focuses primarily on the execution flow by the threads across the different methods, classes and packages.