In debugging, there are "step into", "step over" etc., but what about a "step back" feature? There are chances that when you hit a "step over" twice by mistake, or when you find out it might be just the previous line which is causing trouble, you just want a "roll back" feature.
Debugging is like traversal on a tree or on a graph. Every breakpoint is a state or a node. In theory, if we save these states, we can step back and forth among any of them. Snapshot, versioning or savepoint can be useful in helping save the debugging states.
There are already such support in C/C++ debuggers like gdb. However, it seems that no Java debugger supports "step back" or "roll back". It would be even nicer if such feature could be included in Eclipse IDE.