Java - 在多线程中使用可重入锁

Question

I'm making a program with multi-threading, and I want to use a lock. The problem is the program runs on a thread, and I want to have a Thread that grabs the lock, to pause the first Thread, then be able unlock it when a method is called from a third Thread. I tried a bunch of different things, but none of them worked. How should I do this?

EDIT:

Rewrote the question

Answer 1

As I understand, you want a thread to sleep and wait for the notification from another thread. You should look at Observer and Observable instead of locking.