When two locks are held simultaneously, a ``++wait++`` call only releases one of them. The other will be held until some other thread requests a lock on the awaited object. If no unrelated code tries to lock on that object, then all other threads will be locked out, resulting in a deadlock.
=== Noncompliant code example
[source,java]
----
synchronized (this.mon1) { // threadB can't enter this block to request this.mon2 lock & release threadA
synchronized (this.mon2) {
this.mon2.wait(); // Noncompliant; threadA is stuck here holding lock on this.mon1