Question

I have a application which randomly freezes, including the IDE and it’s driving me mad. That makes me wonder:

What’s a good general strategy for finding the cause of random freezes?

Answer 1

If you’re lucky, you can run your code in a debugger until it freezes, then stop the debugger to find the offending line of code. But if it were that easy, you probably wouldn’t be asking for advice. 🙂

Two strategies that can be used together are to “divide and conquer” and “leave bread crumbs.”

Divide and conquer: Comment out increasingly larger portions of your code. If it still freezes, you’ve reduced the amount of code that might be responsible for causing the freeze. Caveat: eventually you’ll comment out some code and the program will not freeze. This doesn’t mean that last bit of code is necessarily responsible for the freeze; it’s just somehow involved. Put it back and comment out something else.

Leave bread crumbs: Make your program tell you where it is and what it’s doing as it executes. Display a message, add to a log file, make a sound, or send a packet over the network. Is the execution path as you expected? What was the last thing it was doing before it froze? Again, be aware that the last message may have come from a different thread than the one responsible for freezing the program, but as you get closer to the cause you’ll adjust what and where the code logs.