synchronized keyword 설명의 가장 하단을 보면,
http://docs.oracle.com/javase/tutorial/essential/concurrency/locksync.html
같은 thread 내에서는 문제 없군요. 재접근적(reenterant)이라고 하네요. 말씀하신 부분에서 dead lock 은 발생하지 않겠군요.
Reentrant Synchronization
Recall that a thread cannot acquire a lock owned by another thread. But a thread can acquire a lock that it already owns. Allowing a thread to acquire the same lock more than once enables reentrant synchronization. This describes a situation where synchronized code, directly or indirectly, invokes a method that also contains synchronized code, and both sets of code use the same lock. Without reentrant synchronization, synchronized code would have to take many additional precautions to avoid having a thread cause itself to block.