ject in exclusive mode. Only one thread can lock object in exclusive mode at each moment of time. Shared or exclusive lock requests of other threads will be blocked until this lock is released.

Shared locks, but not exclusive locks, can be set on this object until this lock is released.<BR> 
This lock is reentrant so thread owning the lock can successfully retrieve the lock many times (and correspondent number of unlocks is needed to release the lock).<BR> 
Locking the object doesn't prevent other threads 