Sometimes, there's no substitute for println debugging. Particularly with real-time, concurrent code where you're interacting with an external system, bringing

Sometimes, there's no substitute for println debugging. Particularly with real-time, concurrent code where you're interacting with an external system, bringing a thread to a halt in your debugger causes all sorts of false-positive timeout bugs. You get about one shot to break with the debugger, then your state is trashed and you have to start over.