ReentrantLock unlocking in called method

ReentrantLock

void a() {

    lock.lock();    //got intrinsic lock 
    System.out.println(Thread.currentThread().getName());
    System.out.println("In A");
    b();            // called method in synchronized block

    Thread.sleep(2000);    // sleeping current thread(avoided try catch for simplicity) 


    System.out.println("after calling method B()");
    System.out.println(Thread.currentThread().getName());

    lock.unlock();    // releasing intrinsic lock

}

void b() {

    lock.lock();// getting intrinsic lock, no problem as calling thread already has intrinsic lock 
    System.out.println(Thread.currentThread().getName());
    System.out.println("In B");
    lock.unlock();    // intentionally releasing lock, so now there is no lock .

        Thread.sleep(2000);
}

Two threads are spawned Thread- 0 and Thread-1 both are calling a().

In a(), I am getting intrinsic lock and than I'm calling b(). In b() also I'm getting intrinsic lock so I'll get the same lock possessed by current thread. Now I'm intentionally unlocking in b() which releases the lock so that other waiting thread could get the lock, just to make sure I even made current thread sleep . While my thread is sleeping in b() for 2000 ms and than in a() for 2000 ms I was expecting other thread would run a() by getting the released lock.

But its not happening as per my output

Output :-

Thread-0
In A
Thread-0
In B
after calling method B()
Thread-0
Thread-1
In A
Thread-1
In B
after calling method B()
Thread-1