> The write of the default value (zero, false or null) to each variable synchronizes-with the first action in every thread. Although it may seem a little strange to write a default value to a variable before the object containing the variable is allocated, conceptually every object is created at the start of the program with its default initialized values.

I can't get that to jibe in my memory though against:

> The final action in a thread T1 synchronizes-with any action in another thread T2 that detects that T1 has terminated.

> T2 may accomplish this by calling T1.isAlive() or T1.join().

If we were looking into the threads, it would have been obvious that we should wait for the thread to finish before expecting to find a completed value in it other than the default. That's not what happened.

It's unfortunate that I didn't get a copy of the code in question, because it was a genuine idiosyncrasy in Java and by the time I got around to asking my friend for a copy, he had already rewritten his code in a different way that didn't hit the same bug.

Didn't use revision control, got his degree didn't care to repeat the same miserable exercises, now probably hacking ruby in his day job like me (except I promise I'm using revision control.)