Editing Code While Debugging
JDWP allows you to make limited changes to the code while in the debugger without recompiling and restarting the server. You can change the code in the debugger so long as you don't change the method signatures in the class. Saved changes within the editor stopped in debug are saved back into the running process allowing you to re-test your code immediately. If you make significant changes and a re-compile / restart is required, Studio will display a message to this effect.