Object o = new Object();
@Test
public void test1() throws Exception {
    new Thread(new Runnable() {
        @Override
        public void run() {
            synchronized(o) {
                System.out.println("child thread: holdLock: " + 
                    Thread.holdsLock(o));
            }
        }
    }).start();
    System.out.println("main thread: holdLock: " + Thread.holdsLock(o));
    Thread.sleep(2000);
}