Wow! You are certainly asking a large number of
thread questions...
Anyway... classic case.
- thread 1 calls synchronized method of class a
- thread 2 calls synchronized method of class b
Hence, thread 1 owns lock a, and thread 2 owns lock b.
- thread 1 in method of class a tries to call synchronized method of class b. it will block because thread 2 owns lock b.
- thread 2 in method of class b tries to call synchronized method of class a. it will block because thread 1 owns lock a.
Hence, thread 1 owns a and waiting for b, thread 2 owns b and waiting for a. Neither will release their lock because it is waiting for the other one.
Henry
