import java.util.concurrent.locks.ReentrantLock;

public class TestLockDebug {
    public static void main(String[] args) {
        Object lock1 = new Object();
        ReentrantLock lock2 = new ReentrantLock();
        try {
            lock2.lock();
            synchronized (lock1) {
                try {
                    Thread.sleep(100000);
                }
                catch (InterruptedException ignore) {
                }
            }
        }
        finally {
            lock2.unlock();
        }
    }
}

Using JDK 6u23:

Eclipse Helios Release Build id: 20100617-1415:
Thread [main] (Suspended)	
	owns: Object  (id=15)	
	Thread.sleep(long) line: not available [native method]	
	TestLockDebug.main(String[]) line: 13	

VisualVM 1.3.1 thread dump:
"main" prio=6 tid=0x003b8400 nid=0x1120 waiting on condition [0x0090f000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
	at java.lang.Thread.sleep(Native Method)
	at TestLockDebug.main(TestLockDebug.java:13)
	- locked <0x02e60c30> (a java.lang.Object)

   Locked ownable synchronizers:
	- <0x02e6c600> (a java.util.concurrent.locks.ReentrantLock$NonfairSync)