--- jsr166/src/test/tck/ReentrantReadWriteLockTest.java	2003/12/04 20:54:46	1.7
+++ jsr166/src/test/tck/ReentrantReadWriteLockTest.java	2011/05/07 11:15:04	1.57
@@ -1,50 +1,47 @@
 /*
- * Written by members of JCP JSR-166 Expert Group and released to the
- * public domain. Use, modify, and redistribute this code in any way
- * without acknowledgement. Other contributors include Andrew Wright,
- * Jeffrey Hayes, Pat Fischer, Mike Judd.
+ * Written by Doug Lea with assistance from members of JCP JSR-166
+ * Expert Group and released to the public domain, as explained at
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ * Other contributors include Andrew Wright, Jeffrey Hayes,
+ * Pat Fisher, Mike Judd.
  */
 
 import junit.framework.*;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.locks.*;
 import java.util.concurrent.*;
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import java.io.*;
 import java.util.*;
 
 public class ReentrantReadWriteLockTest extends JSR166TestCase {
     public static void main(String[] args) {
-	junit.textui.TestRunner.run (suite());	
+        junit.textui.TestRunner.run(suite());
     }
     public static Test suite() {
-	return new TestSuite(ReentrantReadWriteLockTest.class);
+        return new TestSuite(ReentrantReadWriteLockTest.class);
     }
 
     /**
      * A runnable calling lockInterruptibly
      */
-    class InterruptibleLockRunnable implements Runnable {
+    class InterruptibleLockRunnable extends CheckedRunnable {
         final ReentrantReadWriteLock lock;
         InterruptibleLockRunnable(ReentrantReadWriteLock l) { lock = l; }
-        public void run() {
-            try {
-                lock.writeLock().lockInterruptibly();
-            } catch(InterruptedException success){}
+        public void realRun() throws InterruptedException {
+            lock.writeLock().lockInterruptibly();
         }
     }
 
-
     /**
      * A runnable calling lockInterruptibly that expects to be
      * interrupted
      */
-    class InterruptedLockRunnable implements Runnable {
+    class InterruptedLockRunnable extends CheckedInterruptedRunnable {
         final ReentrantReadWriteLock lock;
         InterruptedLockRunnable(ReentrantReadWriteLock l) { lock = l; }
-        public void run() {
-            try {
-                lock.writeLock().lockInterruptibly();
-                threadShouldThrow();
-            } catch(InterruptedException success){}
+        public void realRun() throws InterruptedException {
+            lock.writeLock().lockInterruptibly();
         }
     }
 
@@ -53,1032 +50,1415 @@ public class ReentrantReadWriteLockTest
      */
     static class PublicReentrantReadWriteLock extends ReentrantReadWriteLock {
         PublicReentrantReadWriteLock() { super(); }
-        public Collection<Thread> getQueuedThreads() { 
-            return super.getQueuedThreads(); 
+        public Collection<Thread> getQueuedThreads() {
+            return super.getQueuedThreads();
         }
-        public PublicCondition newCondition() { 
-            return new PublicCondition(this);
+        public Collection<Thread> getWaitingThreads(Condition c) {
+            return super.getWaitingThreads(c);
         }
+    }
+
+    /**
+     * Releases write lock, checking that it had a hold count of 1.
+     */
+    void releaseWriteLock(ReentrantReadWriteLock lock) {
+        ReentrantReadWriteLock.WriteLock writeLock = lock.writeLock();
+        assertTrue(writeLock.isHeldByCurrentThread());
+        writeLock.unlock();
+        assertFalse(writeLock.isHeldByCurrentThread());
+    }
 
-        static class PublicCondition extends AbstractReentrantLock.ConditionObject {
-            PublicCondition(PublicReentrantReadWriteLock l) { super(l); }
-            public Collection<Thread> getWaitingThreads() { 
-                return super.getWaitingThreads(); 
-            }
+    /**
+     * Spin-waits until lock.hasQueuedThread(t) becomes true.
+     */
+    void waitForQueuedThread(ReentrantReadWriteLock lock, Thread t) {
+        long startTime = System.nanoTime();
+        while (!lock.hasQueuedThread(t)) {
+            if (millisElapsedSince(startTime) > LONG_DELAY_MS)
+                throw new AssertionError("timed out");
+            Thread.yield();
         }
+    }
+
+    /**
+     * Checks that lock is not write-locked.
+     */
+    void assertNotWriteLocked(ReentrantReadWriteLock lock) {
+        assertFalse(lock.isWriteLocked());
+        assertFalse(lock.isWriteLockedByCurrentThread());
+        assertEquals(0, lock.getWriteHoldCount());
+    }
+
+    /**
+     * Checks that condition c has no waiters.
+     */
+    void assertHasNoWaiters(PublicReentrantReadWriteLock lock, Condition c) {
+        assertHasWaiters(lock, c, new Thread[] {});
+    }
 
+    /**
+     * Checks that condition c has exactly the given waiter threads.
+     */
+    void assertHasWaiters(PublicReentrantReadWriteLock lock, Condition c,
+                          Thread... threads) {
+        lock.writeLock().lock();
+        assertEquals(threads.length > 0, lock.hasWaiters(c));
+        assertEquals(threads.length, lock.getWaitQueueLength(c));
+        assertEquals(threads.length == 0, lock.getWaitingThreads(c).isEmpty());
+        assertEquals(threads.length, lock.getWaitingThreads(c).size());
+        assertEquals(new HashSet<Thread>(lock.getWaitingThreads(c)),
+                     new HashSet<Thread>(Arrays.asList(threads)));
+        lock.writeLock().unlock();
     }
 
     /**
      * Constructor sets given fairness, and is in unlocked state
      */
-    public void testConstructor() { 
-	ReentrantReadWriteLock rl = new ReentrantReadWriteLock();
+    public void testConstructor() {
+        ReentrantReadWriteLock rl = new ReentrantReadWriteLock();
         assertFalse(rl.isFair());
         assertFalse(rl.isWriteLocked());
-        assertEquals(0, rl.getReadLocks());
-	ReentrantReadWriteLock r2 = new ReentrantReadWriteLock(true);
+        assertEquals(0, rl.getReadLockCount());
+        ReentrantReadWriteLock r2 = new ReentrantReadWriteLock(true);
         assertTrue(r2.isFair());
         assertFalse(r2.isWriteLocked());
-        assertEquals(0, r2.getReadLocks());
+        assertEquals(0, r2.getReadLockCount());
+        ReentrantReadWriteLock r3 = new ReentrantReadWriteLock(false);
+        assertFalse(r3.isFair());
+        assertFalse(r3.isWriteLocked());
+        assertEquals(0, r3.getReadLockCount());
     }
 
     /**
      * write-locking and read-locking an unlocked lock succeed
      */
-    public void testLock() { 
-	ReentrantReadWriteLock rl = new ReentrantReadWriteLock();
+    public void testLock() {
+        ReentrantReadWriteLock rl = new ReentrantReadWriteLock();
         rl.writeLock().lock();
         assertTrue(rl.isWriteLocked());
         assertTrue(rl.isWriteLockedByCurrentThread());
-        assertEquals(0, rl.getReadLocks());
+        assertTrue(rl.writeLock().isHeldByCurrentThread());
+        assertEquals(0, rl.getReadLockCount());
         rl.writeLock().unlock();
         assertFalse(rl.isWriteLocked());
         assertFalse(rl.isWriteLockedByCurrentThread());
-        assertEquals(0, rl.getReadLocks());
+        assertFalse(rl.writeLock().isHeldByCurrentThread());
+        assertEquals(0, rl.getReadLockCount());
         rl.readLock().lock();
         assertFalse(rl.isWriteLocked());
         assertFalse(rl.isWriteLockedByCurrentThread());
-        assertEquals(1, rl.getReadLocks());
+        assertEquals(1, rl.getReadLockCount());
         rl.readLock().unlock();
         assertFalse(rl.isWriteLocked());
         assertFalse(rl.isWriteLockedByCurrentThread());
-        assertEquals(0, rl.getReadLocks());
+        assertEquals(0, rl.getReadLockCount());
     }
 
-
     /**
      * locking an unlocked fair lock succeeds
      */
-    public void testFairLock() { 
-	ReentrantReadWriteLock rl = new ReentrantReadWriteLock(true);
+    public void testFairLock() {
+        ReentrantReadWriteLock rl = new ReentrantReadWriteLock(true);
         rl.writeLock().lock();
         assertTrue(rl.isWriteLocked());
         assertTrue(rl.isWriteLockedByCurrentThread());
-        assertEquals(0, rl.getReadLocks());
+        assertTrue(rl.writeLock().isHeldByCurrentThread());
+        assertEquals(0, rl.getReadLockCount());
         rl.writeLock().unlock();
         assertFalse(rl.isWriteLocked());
         assertFalse(rl.isWriteLockedByCurrentThread());
-        assertEquals(0, rl.getReadLocks());
+        assertFalse(rl.writeLock().isHeldByCurrentThread());
+        assertEquals(0, rl.getReadLockCount());
         rl.readLock().lock();
         assertFalse(rl.isWriteLocked());
         assertFalse(rl.isWriteLockedByCurrentThread());
-        assertEquals(1, rl.getReadLocks());
+        assertEquals(1, rl.getReadLockCount());
         rl.readLock().unlock();
         assertFalse(rl.isWriteLocked());
         assertFalse(rl.isWriteLockedByCurrentThread());
-        assertEquals(0, rl.getReadLocks());
+        assertEquals(0, rl.getReadLockCount());
     }
 
     /**
      * getWriteHoldCount returns number of recursive holds
      */
-    public void testGetHoldCount() {
-	ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	for(int i = 1; i <= SIZE; i++) {
-	    lock.writeLock().lock();
-	    assertEquals(i,lock.getWriteHoldCount());
-	}
-	for(int i = SIZE; i > 0; i--) {
-	    lock.writeLock().unlock();
-	    assertEquals(i-1,lock.getWriteHoldCount());
-	}
-    }
-    
-
-    /**
-     * write-unlocking an unlocked lock throws IllegalMonitorStateException
-     */
-    public void testUnlock_IllegalMonitorStateException() { 
-	ReentrantReadWriteLock rl = new ReentrantReadWriteLock();
-	try {
-	    rl.writeLock().unlock();
-	    shouldThrow();
-	} catch(IllegalMonitorStateException success){}
-    }
-
-
-    /**
-     * write-lockInterruptibly is interruptible
-     */
-    public void testWriteLockInterruptibly_Interrupted() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	lock.writeLock().lock();
-	Thread t = new Thread(new Runnable() {
-                public void run() {
-                    try {
-			lock.writeLock().lockInterruptibly();
-			threadShouldThrow();
-		    } catch(InterruptedException success){}
-		}
-	    });
-        try {
-            t.start();
-            t.interrupt();
-            lock.writeLock().unlock();
-            t.join();
-        } catch(Exception e){
-            unexpectedException();
+    public void testGetWriteHoldCount() {
+        ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        for (int i = 1; i <= SIZE; i++) {
+            lock.writeLock().lock();
+            assertEquals(i,lock.getWriteHoldCount());
         }
-    } 
-
-    /**
-     * timed write-trylock is interruptible
-     */
-    public void testWriteTryLock_Interrupted() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	lock.writeLock().lock();
-	Thread t = new Thread(new Runnable() {
-                public void run() {
-                    try {
-			lock.writeLock().tryLock(1000,TimeUnit.MILLISECONDS);
-			threadShouldThrow();
-		    } catch(InterruptedException success){}
-		}
-	    });
-        try {
-            t.start();
-            t.interrupt();
+        for (int i = SIZE; i > 0; i--) {
             lock.writeLock().unlock();
-            t.join();
-        } catch(Exception e){
-            unexpectedException();
+            assertEquals(i-1,lock.getWriteHoldCount());
         }
     }
 
     /**
-     * read-lockInterruptibly is interruptible
+     * WriteLock.getHoldCount returns number of recursive holds
      */
-    public void testReadLockInterruptibly_Interrupted() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	lock.writeLock().lock();
-	Thread t = new Thread(new Runnable() {
-                public void run() {
-                    try {
-			lock.readLock().lockInterruptibly();
-			threadShouldThrow();
-		    } catch(InterruptedException success){}
-		}
-	    });
-        try {
-            t.start();
-            t.interrupt();
+    public void testGetHoldCount() {
+        ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        for (int i = 1; i <= SIZE; i++) {
+            lock.writeLock().lock();
+            assertEquals(i,lock.writeLock().getHoldCount());
+        }
+        for (int i = SIZE; i > 0; i--) {
             lock.writeLock().unlock();
-            t.join();
-        } catch(Exception e){
-            unexpectedException();
+            assertEquals(i-1,lock.writeLock().getHoldCount());
         }
-    } 
+    }
 
     /**
-     * timed read-trylock is interruptible
+     * getReadHoldCount returns number of recursive holds
      */
-    public void testReadTryLock_Interrupted() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	lock.writeLock().lock();
-	Thread t = new Thread(new Runnable() {
-                public void run() {
-                    try {
-			lock.readLock().tryLock(1000,TimeUnit.MILLISECONDS);
-			threadShouldThrow();
-		    } catch(InterruptedException success){}
-		}
-	    });
-        try {
-            t.start();
-            t.interrupt();
-            t.join();
-        } catch(Exception e){
-            unexpectedException();
+    public void testGetReadHoldCount() {
+        ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        for (int i = 1; i <= SIZE; i++) {
+            lock.readLock().lock();
+            assertEquals(i,lock.getReadHoldCount());
+        }
+        for (int i = SIZE; i > 0; i--) {
+            lock.readLock().unlock();
+            assertEquals(i-1,lock.getReadHoldCount());
         }
     }
 
-    
     /**
-     * write-trylock fails if locked
+     * write-unlocking an unlocked lock throws IllegalMonitorStateException
      */
-    public void testWriteTryLockWhenLocked() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	lock.writeLock().lock();
-	Thread t = new Thread(new Runnable() {
-                public void run() {
-                    threadAssertFalse(lock.writeLock().tryLock());
-		}
-	    });
+    public void testWriteUnlock_IllegalMonitorStateException() {
+        ReentrantReadWriteLock rl = new ReentrantReadWriteLock();
         try {
-            t.start();
-            t.join();
-            lock.writeLock().unlock();
-        } catch(Exception e){
-            unexpectedException();
-        }
-    } 
+            rl.writeLock().unlock();
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
+    }
 
     /**
-     * read-trylock fails if locked
+     * read-unlocking an unlocked lock throws IllegalMonitorStateException
      */
-    public void testReadTryLockWhenLocked() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	lock.writeLock().lock();
-	Thread t = new Thread(new Runnable() {
-                public void run() {
-                    threadAssertFalse(lock.readLock().tryLock());
-		}
-	    });
+    public void testReadUnlock_IllegalMonitorStateException() {
+        ReentrantReadWriteLock rl = new ReentrantReadWriteLock();
         try {
-            t.start();
-            t.join();
-            lock.writeLock().unlock();
-        } catch(Exception e){
-            unexpectedException();
-        }
-    } 
+            rl.readLock().unlock();
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
+    }
 
     /**
-     * Multiple threads can hold a read lock when not write-locked
+     * write-lockInterruptibly is interruptible
      */
-    public void testMultipleReadLocks() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	lock.readLock().lock();
-	Thread t = new Thread(new Runnable() {
-                public void run() {
-                    threadAssertTrue(lock.readLock().tryLock());
-                    lock.readLock().unlock();
-		}
-	    });
-        try {
-            t.start();
-            t.join();
-            lock.readLock().unlock();
-        } catch(Exception e){
-            unexpectedException();
-        }
-    } 
+    public void testWriteLockInterruptibly_Interrupted() throws Exception {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lock();
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.writeLock().lockInterruptibly();
+            }});
+
+        waitForQueuedThread(lock, t);
+        t.interrupt();
+        awaitTermination(t);
+        releaseWriteLock(lock);
+    }
 
     /**
-     * A writelock succeeds after reading threads unlock
+     * timed write-tryLock is interruptible
      */
-    public void testWriteAfterMultipleReadLocks() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	lock.readLock().lock();
-	Thread t1 = new Thread(new Runnable() {
-                public void run() {
-                    lock.readLock().lock();
-                    lock.readLock().unlock();
-		}
-	    });
-	Thread t2 = new Thread(new Runnable() {
-                public void run() {
-                    lock.writeLock().lock();
-                    lock.writeLock().unlock();
-		}
-	    });
+    public void testWriteTryLock_Interrupted() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lock();
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.writeLock().tryLock(LONG_DELAY_MS, MILLISECONDS);
+            }});
 
-        try {
-            t1.start();
-            t2.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            lock.readLock().unlock();
-            t1.join(MEDIUM_DELAY_MS);
-            t2.join(MEDIUM_DELAY_MS);
-            assertTrue(!t1.isAlive());
-            assertTrue(!t2.isAlive());
-           
-        } catch(Exception e){
-            unexpectedException();
-        }
-    } 
+        waitForQueuedThread(lock, t);
+        t.interrupt();
+        awaitTermination(t);
+        releaseWriteLock(lock);
+    }
 
     /**
-     * Readlocks succeed after a writing thread unlocks
+     * read-lockInterruptibly is interruptible
      */
-    public void testReadAfterWriteLock() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	lock.writeLock().lock();
-	Thread t1 = new Thread(new Runnable() {
-                public void run() {
-                    lock.readLock().lock();
-                    lock.readLock().unlock();
-		}
-	    });
-	Thread t2 = new Thread(new Runnable() {
-                public void run() {
-                    lock.readLock().lock();
-                    lock.readLock().unlock();
-		}
-	    });
-
-        try {
-            t1.start();
-            t2.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            lock.writeLock().unlock();
-            t1.join(MEDIUM_DELAY_MS);
-            t2.join(MEDIUM_DELAY_MS);
-            assertTrue(!t1.isAlive());
-            assertTrue(!t2.isAlive());
-           
-        } catch(Exception e){
-            unexpectedException();
-        }
-    } 
+    public void testReadLockInterruptibly_Interrupted() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lock();
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.readLock().lockInterruptibly();
+            }});
 
+        waitForQueuedThread(lock, t);
+        t.interrupt();
+        awaitTermination(t);
+        releaseWriteLock(lock);
+    }
 
     /**
-     * Read trylock succeeds if readlocked but not writelocked
+     * timed read-tryLock is interruptible
      */
-    public void testTryLockWhenReadLocked() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	lock.readLock().lock();
-	Thread t = new Thread(new Runnable() {
-                public void run() {
-                    threadAssertTrue(lock.readLock().tryLock());
-                    lock.readLock().unlock();
-		}
-	    });
-        try {
-            t.start();
-            t.join();
-            lock.readLock().unlock();
-        } catch(Exception e){
-            unexpectedException();
-        }
-    } 
+    public void testReadTryLock_Interrupted() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lock();
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.readLock().tryLock(LONG_DELAY_MS, MILLISECONDS);
+            }});
 
-    
+        waitForQueuedThread(lock, t);
+        t.interrupt();
+        awaitTermination(t);
+        releaseWriteLock(lock);
+    }
 
     /**
-     * write trylock fails when readlocked
+     * write-tryLock fails if locked
      */
-    public void testWriteTryLockWhenReadLocked() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	lock.readLock().lock();
-	Thread t = new Thread(new Runnable() {
-                public void run() {
-                    threadAssertFalse(lock.writeLock().tryLock());
-		}
-	    });
-        try {
-            t.start();
-            t.join();
-            lock.readLock().unlock();
-        } catch(Exception e){
-            unexpectedException();
-        }
-    } 
+    public void testWriteTryLockWhenLocked() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                assertFalse(lock.writeLock().tryLock());
+            }});
 
-    
+        awaitTermination(t);
+        releaseWriteLock(lock);
+    }
 
     /**
-     * write timed trylock times out if locked
+     * read-tryLock fails if locked
      */
-    public void testWriteTryLock_Timeout() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	lock.writeLock().lock();
-	Thread t = new Thread(new Runnable() {
-                public void run() {
-		    try {
-                        threadAssertFalse(lock.writeLock().tryLock(1, TimeUnit.MILLISECONDS));
-                    } catch (Exception ex) {
-                        threadUnexpectedException();
-                    }
-		}
-	    });
-        try {
-            t.start();
-            t.join();
-            lock.writeLock().unlock();
-        } catch(Exception e){
-            unexpectedException();
-        }
-    } 
+    public void testReadTryLockWhenLocked() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                assertFalse(lock.readLock().tryLock());
+            }});
+
+        awaitTermination(t);
+        releaseWriteLock(lock);
+    }
 
     /**
-     * read timed trylock times out if write-locked
+     * Multiple threads can hold a read lock when not write-locked
      */
-    public void testReadTryLock_Timeout() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	lock.writeLock().lock();
-	Thread t = new Thread(new Runnable() {
-                public void run() {
-		    try {
-                        threadAssertFalse(lock.readLock().tryLock(1, TimeUnit.MILLISECONDS));
-                    } catch (Exception ex) {
-                        threadUnexpectedException();
-                    }
-		}
-	    });
-        try {
-            t.start();
-            t.join();
-            lock.writeLock().unlock();
-        } catch(Exception e){
-            unexpectedException();
-        }
-    } 
-
+    public void testMultipleReadLocks() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.readLock().lock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                assertTrue(lock.readLock().tryLock());
+                lock.readLock().unlock();
+            }});
+
+        awaitTermination(t);
+        lock.readLock().unlock();
+    }
+
+    /**
+     * A writelock succeeds only after reading threads unlock
+     */
+    public void testWriteAfterMultipleReadLocks() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.readLock().lock();
+        Thread t1 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.readLock().lock();
+                lock.readLock().unlock();
+            }});
+        Thread t2 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.writeLock().lock();
+                lock.writeLock().unlock();
+            }});
+        delay(SHORT_DELAY_MS);
+        lock.readLock().unlock();
+        awaitTermination(t1);
+        awaitTermination(t2);
+        assertNotWriteLocked(lock);
+    }
+
+    /**
+     * Readlocks succeed only after a writing thread unlocks
+     */
+    public void testReadAfterWriteLock() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lock();
+        Thread t1 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.readLock().lock();
+                lock.readLock().unlock();
+            }});
+        Thread t2 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.readLock().lock();
+                lock.readLock().unlock();
+            }});
+
+        waitForQueuedThread(lock, t1);
+        waitForQueuedThread(lock, t2);
+        releaseWriteLock(lock);
+        awaitTermination(t1);
+        awaitTermination(t2);
+    }
+
+    /**
+     * Read trylock succeeds if write locked by current thread
+     */
+    public void testReadHoldingWriteLock() {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lock();
+        assertTrue(lock.readLock().tryLock());
+        lock.readLock().unlock();
+        lock.writeLock().unlock();
+    }
+
+    /**
+     * Read lock succeeds if write locked by current thread even if
+     * other threads are waiting for readlock
+     */
+    public void testReadHoldingWriteLock2() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lock();
+        lock.readLock().lock();
+        lock.readLock().unlock();
+
+        Thread t1 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.readLock().lock();
+                lock.readLock().unlock();
+            }});
+        Thread t2 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.readLock().lock();
+                lock.readLock().unlock();
+            }});
+
+        waitForQueuedThread(lock, t1);
+        waitForQueuedThread(lock, t2);
+        assertTrue(lock.isWriteLockedByCurrentThread());
+        lock.readLock().lock();
+        lock.readLock().unlock();
+        releaseWriteLock(lock);
+        awaitTermination(t1);
+        awaitTermination(t2);
+    }
+
+    /**
+     * Read lock succeeds if write locked by current thread even if
+     * other threads are waiting for writelock
+     */
+    public void testReadHoldingWriteLock3() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lock();
+        lock.readLock().lock();
+        lock.readLock().unlock();
+
+        Thread t1 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.writeLock().lock();
+                lock.writeLock().unlock();
+            }});
+        Thread t2 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.writeLock().lock();
+                lock.writeLock().unlock();
+            }});
+
+        waitForQueuedThread(lock, t1);
+        waitForQueuedThread(lock, t2);
+        assertTrue(lock.isWriteLockedByCurrentThread());
+        lock.readLock().lock();
+        lock.readLock().unlock();
+        releaseWriteLock(lock);
+        awaitTermination(t1);
+        awaitTermination(t2);
+    }
+
+    /**
+     * Write lock succeeds if write locked by current thread even if
+     * other threads are waiting for writelock
+     */
+    public void testWriteHoldingWriteLock4() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lock();
+        lock.writeLock().lock();
+        lock.writeLock().unlock();
+
+        Thread t1 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.writeLock().lock();
+                lock.writeLock().unlock();
+            }});
+        Thread t2 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.writeLock().lock();
+                lock.writeLock().unlock();
+            }});
+
+        waitForQueuedThread(lock, t1);
+        waitForQueuedThread(lock, t2);
+        assertTrue(lock.isWriteLockedByCurrentThread());
+        assertEquals(1, lock.getWriteHoldCount());
+        lock.writeLock().lock();
+        assertTrue(lock.isWriteLockedByCurrentThread());
+        assertEquals(2, lock.getWriteHoldCount());
+        lock.writeLock().unlock();
+        releaseWriteLock(lock);
+        awaitTermination(t1);
+        awaitTermination(t2);
+    }
+
+    /**
+     * Fair Read trylock succeeds if write locked by current thread
+     */
+    public void testReadHoldingWriteLockFair() {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
+        lock.writeLock().lock();
+        assertTrue(lock.readLock().tryLock());
+        lock.readLock().unlock();
+        lock.writeLock().unlock();
+    }
+
+    /**
+     * Fair Read lock succeeds if write locked by current thread even if
+     * other threads are waiting for readlock
+     */
+    public void testReadHoldingWriteLockFair2() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
+        lock.writeLock().lock();
+        lock.readLock().lock();
+        lock.readLock().unlock();
+
+        Thread t1 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.readLock().lock();
+                lock.readLock().unlock();
+            }});
+        Thread t2 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.readLock().lock();
+                lock.readLock().unlock();
+            }});
+
+        waitForQueuedThread(lock, t1);
+        waitForQueuedThread(lock, t2);
+        assertTrue(lock.isWriteLockedByCurrentThread());
+        lock.readLock().lock();
+        lock.readLock().unlock();
+        releaseWriteLock(lock);
+        awaitTermination(t1);
+        awaitTermination(t2);
+    }
+
+    /**
+     * Fair Read lock succeeds if write locked by current thread even if
+     * other threads are waiting for writelock
+     */
+    public void testReadHoldingWriteLockFair3() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
+        lock.writeLock().lock();
+        lock.readLock().lock();
+        lock.readLock().unlock();
+
+        Thread t1 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.writeLock().lock();
+                lock.writeLock().unlock();
+            }});
+        Thread t2 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.writeLock().lock();
+                lock.writeLock().unlock();
+            }});
+
+        waitForQueuedThread(lock, t1);
+        waitForQueuedThread(lock, t2);
+        assertTrue(lock.isWriteLockedByCurrentThread());
+        lock.readLock().lock();
+        lock.readLock().unlock();
+        releaseWriteLock(lock);
+        awaitTermination(t1);
+        awaitTermination(t2);
+    }
+
+    /**
+     * Fair Write lock succeeds if write locked by current thread even if
+     * other threads are waiting for writelock
+     */
+    public void testWriteHoldingWriteLockFair4() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
+        lock.writeLock().lock();
+        Thread t1 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.writeLock().lock();
+                lock.writeLock().unlock();
+            }});
+        Thread t2 = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.writeLock().lock();
+                lock.writeLock().unlock();
+            }});
+
+        waitForQueuedThread(lock, t1);
+        waitForQueuedThread(lock, t2);
+        assertTrue(lock.isWriteLockedByCurrentThread());
+        assertEquals(1, lock.getWriteHoldCount());
+        lock.writeLock().lock();
+        assertEquals(2, lock.getWriteHoldCount());
+        lock.writeLock().unlock();
+        lock.writeLock().lock();
+        lock.writeLock().unlock();
+        releaseWriteLock(lock);
+        awaitTermination(t1);
+        awaitTermination(t2);
+    }
+
+    /**
+     * Read tryLock succeeds if readlocked but not writelocked
+     */
+    public void testTryLockWhenReadLocked() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.readLock().lock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                assertTrue(lock.readLock().tryLock());
+                lock.readLock().unlock();
+            }});
+
+        awaitTermination(t);
+        lock.readLock().unlock();
+    }
+
+    /**
+     * write tryLock fails when readlocked
+     */
+    public void testWriteTryLockWhenReadLocked() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.readLock().lock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                assertFalse(lock.writeLock().tryLock());
+            }});
+
+        awaitTermination(t);
+        lock.readLock().unlock();
+    }
+
+    /**
+     * Fair Read tryLock succeeds if readlocked but not writelocked
+     */
+    public void testTryLockWhenReadLockedFair() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
+        lock.readLock().lock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                assertTrue(lock.readLock().tryLock());
+                lock.readLock().unlock();
+            }});
+
+        awaitTermination(t);
+        lock.readLock().unlock();
+    }
+
+    /**
+     * Fair write tryLock fails when readlocked
+     */
+    public void testWriteTryLockWhenReadLockedFair() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock(true);
+        lock.readLock().lock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                assertFalse(lock.writeLock().tryLock());
+            }});
+
+        awaitTermination(t);
+        lock.readLock().unlock();
+    }
+
+    /**
+     * write timed tryLock times out if locked
+     */
+    public void testWriteTryLock_Timeout() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                assertFalse(lock.writeLock().tryLock(1, MILLISECONDS));
+            }});
+
+        awaitTermination(t);
+        assertTrue(lock.writeLock().isHeldByCurrentThread());
+        lock.writeLock().unlock();
+    }
+
+    /**
+     * read timed tryLock times out if write-locked
+     */
+    public void testReadTryLock_Timeout() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lock();
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                assertFalse(lock.readLock().tryLock(1, MILLISECONDS));
+            }});
+
+        awaitTermination(t);
+        assertTrue(lock.writeLock().isHeldByCurrentThread());
+        lock.writeLock().unlock();
+    }
 
     /**
      * write lockInterruptibly succeeds if lock free else is interruptible
      */
-    public void testWriteLockInterruptibly() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	try {
-            lock.writeLock().lockInterruptibly();
-        } catch(Exception e) {
-            unexpectedException();
-        }
-	Thread t = new Thread(new Runnable() { 
-		public void run() {
-		    try {
-			lock.writeLock().lockInterruptibly();
-			threadShouldThrow();
-		    }
-		    catch(InterruptedException success) {
-                    }
-		}
-	    });
-        try {
-            t.start();
-            t.interrupt();
-            t.join();
-            lock.writeLock().unlock();
-        } catch(Exception e){
-            unexpectedException();
-        }
+    public void testWriteLockInterruptibly() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lockInterruptibly();
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.writeLock().lockInterruptibly();
+            }});
+
+        waitForQueuedThread(lock, t);
+        t.interrupt();
+        awaitTermination(t);
+        releaseWriteLock(lock);
     }
 
     /**
-     *  read lockInterruptibly succeeds if lock free else is interruptible
+     * read lockInterruptibly succeeds if lock free else is interruptible
      */
-    public void testReadLockInterruptibly() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
-	try {
-            lock.writeLock().lockInterruptibly();
-        } catch(Exception e) {
-            unexpectedException();
-        }
-	Thread t = new Thread(new Runnable() { 
-		public void run() {
-		    try {
-			lock.readLock().lockInterruptibly();
-			threadShouldThrow();
-		    }
-		    catch(InterruptedException success) {
-                    }
-		}
-	    });
-        try {
-            t.start();
-            t.interrupt();
-            t.join();
-            lock.writeLock().unlock();
-        } catch(Exception e){
-            unexpectedException();
-        }
+    public void testReadLockInterruptibly() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        lock.writeLock().lockInterruptibly();
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.readLock().lockInterruptibly();
+            }});
+
+        waitForQueuedThread(lock, t);
+        t.interrupt();
+        awaitTermination(t);
+        releaseWriteLock(lock);
     }
 
     /**
      * Calling await without holding lock throws IllegalMonitorStateException
      */
-    public void testAwait_IllegalMonitor() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();	
+    public void testAwait_IllegalMonitor() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
         final Condition c = lock.writeLock().newCondition();
         try {
             c.await();
             shouldThrow();
-        }
-        catch (IllegalMonitorStateException success) {
-        }
-        catch (Exception ex) {
+        } catch (IllegalMonitorStateException success) {}
+        try {
+            c.await(LONG_DELAY_MS, MILLISECONDS);
             shouldThrow();
-        }
+        } catch (IllegalMonitorStateException success) {}
+        try {
+            c.awaitNanos(100);
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
+        try {
+            c.awaitUninterruptibly();
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
     }
 
     /**
      * Calling signal without holding lock throws IllegalMonitorStateException
      */
     public void testSignal_IllegalMonitor() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();	
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
         final Condition c = lock.writeLock().newCondition();
         try {
             c.signal();
             shouldThrow();
-        }
-        catch (IllegalMonitorStateException success) {
-        }
-        catch (Exception ex) {
-            unexpectedException();
-        }
+        } catch (IllegalMonitorStateException success) {}
     }
 
     /**
-     * awaitNanos without a signal times out
+     * Calling signalAll without holding lock throws IllegalMonitorStateException
      */
-    public void testAwaitNanos_Timeout() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();	
+    public void testSignalAll_IllegalMonitor() {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
         final Condition c = lock.writeLock().newCondition();
         try {
-            lock.writeLock().lock();
-            long t = c.awaitNanos(100);
-            assertTrue(t <= 0);
-            lock.writeLock().unlock();
-        }
-        catch (Exception ex) {
-            unexpectedException();
-        }
+            c.signalAll();
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
     }
 
+    /**
+     * awaitNanos without a signal times out
+     */
+    public void testAwaitNanos_Timeout() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        final Condition c = lock.writeLock().newCondition();
+        lock.writeLock().lock();
+        long startTime = System.nanoTime();
+        long timeoutMillis = 10;
+        long timeoutNanos = MILLISECONDS.toNanos(timeoutMillis);
+        long nanosRemaining = c.awaitNanos(timeoutNanos);
+        assertTrue(nanosRemaining <= 0);
+        assertTrue(millisElapsedSince(startTime) >= timeoutMillis);
+        lock.writeLock().unlock();
+    }
 
     /**
-     *  timed await without a signal times out
+     * timed await without a signal times out
      */
-    public void testAwait_Timeout() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();	
+    public void testAwait_Timeout() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
         final Condition c = lock.writeLock().newCondition();
-        try {
-            lock.writeLock().lock();
-            assertFalse(c.await(10, TimeUnit.MILLISECONDS));
-            lock.writeLock().unlock();
-        }
-        catch (Exception ex) {
-            unexpectedException();
-        }
+        lock.writeLock().lock();
+        long startTime = System.nanoTime();
+        long timeoutMillis = 10;
+        assertFalse(c.await(timeoutMillis, MILLISECONDS));
+        assertTrue(millisElapsedSince(startTime) >= timeoutMillis);
+        lock.writeLock().unlock();
     }
 
     /**
      * awaitUntil without a signal times out
      */
-    public void testAwaitUntil_Timeout() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();	
+    public void testAwaitUntil_Timeout() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
         final Condition c = lock.writeLock().newCondition();
-        try {
-            lock.writeLock().lock();
-            java.util.Date d = new java.util.Date();
-            assertFalse(c.awaitUntil(new java.util.Date(d.getTime() + 10)));
-            lock.writeLock().unlock();
-        }
-        catch (Exception ex) {
-            unexpectedException();
-        }
+        lock.writeLock().lock();
+        java.util.Date d = new java.util.Date();
+        assertFalse(c.awaitUntil(new java.util.Date(d.getTime() + 10)));
+        lock.writeLock().unlock();
     }
 
     /**
      * await returns when signalled
      */
-    public void testAwait() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();	
+    public void testAwait() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
         final Condition c = lock.writeLock().newCondition();
-	Thread t = new Thread(new Runnable() { 
-		public void run() {
-		    try {
-			lock.writeLock().lock();
-                        c.await();
-                        lock.writeLock().unlock();
-		    }
-		    catch(InterruptedException e) {
-                        threadUnexpectedException();
-                    }
-		}
-	    });
-
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            lock.writeLock().lock();
-            c.signal();
-            lock.writeLock().unlock();
-            t.join(SHORT_DELAY_MS);
-            assertFalse(t.isAlive());
-        }
-        catch (Exception ex) {
-            unexpectedException();
-        }
+        final CountDownLatch locked = new CountDownLatch(1);
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.writeLock().lock();
+                locked.countDown();
+                c.await();
+                lock.writeLock().unlock();
+            }});
+
+        locked.await();
+        lock.writeLock().lock();
+        c.signal();
+        assertTrue(t.isAlive());
+        lock.writeLock().unlock();
+        awaitTermination(t);
     }
 
     /**
      * awaitUninterruptibly doesn't abort on interrupt
      */
-    public void testAwaitUninterruptibly() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();	
+    public void testAwaitUninterruptibly() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
         final Condition c = lock.writeLock().newCondition();
-	Thread t = new Thread(new Runnable() { 
-		public void run() {
-                    lock.writeLock().lock();
-                    c.awaitUninterruptibly();
-                    lock.writeLock().unlock();
-		}
-	    });
-
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            t.interrupt();
-            lock.writeLock().lock();
-            c.signal();
-            lock.writeLock().unlock();
-            assert(t.isInterrupted());
-            t.join(SHORT_DELAY_MS);
-            assertFalse(t.isAlive());
-        }
-        catch (Exception ex) {
-            unexpectedException();
-        }
+        final CountDownLatch locked = new CountDownLatch(1);
+        final AtomicBoolean canAwake = new AtomicBoolean(false);
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() {
+                lock.writeLock().lock();
+                locked.countDown();
+                c.awaitUninterruptibly();
+                assertTrue(Thread.interrupted());
+                lock.writeLock().unlock();
+            }});
+
+        locked.await();
+        lock.writeLock().lock();
+        lock.writeLock().unlock();
+        t.interrupt();
+        t.join(10);
+        assertTrue(t.isAlive());
+        lock.writeLock().lock();
+        c.signal();
+        lock.writeLock().unlock();
+        awaitTermination(t);
     }
 
     /**
      * await is interruptible
      */
-    public void testAwait_Interrupt() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();	
+    public void testAwait_Interrupt() throws InterruptedException {
+        final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();
         final Condition c = lock.writeLock().newCondition();
-	Thread t = new Thread(new Runnable() { 
-		public void run() {
-		    try {
-			lock.writeLock().lock();
-                        c.await();
-                        lock.writeLock().unlock();
-                        threadShouldThrow();
-		    }
-		    catch(InterruptedException success) {
-                    }
-		}
-	    });
-
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            t.interrupt();
-            t.join(SHORT_DELAY_MS);
-            assertFalse(t.isAlive());
-        }
-        catch (Exception ex) {
-            unexpectedException();
-        }
+        final CountDownLatch locked = new CountDownLatch(1);
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.writeLock().lock();
+                assertTrue(lock.isWriteLocked());
+                assertTrue(lock.isWriteLockedByCurrentThread());
+                assertHasNoWaiters(lock, c);
+                locked.countDown();
+                try {
+                    c.await();
+                } finally {
+                    assertTrue(lock.isWriteLocked());
+                    assertTrue(lock.isWriteLockedByCurrentThread());
+                    assertHasNoWaiters(lock, c);
+                    lock.writeLock().unlock();
+                    assertFalse(Thread.interrupted());
+                }
+            }});
+
+        locked.await();
+        assertHasWaiters(lock, c, t);
+        t.interrupt();
+        awaitTermination(t);
+        assertFalse(lock.isWriteLocked());
     }
 
     /**
      * awaitNanos is interruptible
      */
-    public void testAwaitNanos_Interrupt() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();	
+    public void testAwaitNanos_Interrupt() throws InterruptedException {
+        final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();
         final Condition c = lock.writeLock().newCondition();
-	Thread t = new Thread(new Runnable() { 
-		public void run() {
-		    try {
-			lock.writeLock().lock();
-                        c.awaitNanos(SHORT_DELAY_MS * 2 * 1000000);
-                        lock.writeLock().unlock();
-                        threadShouldThrow();
-		    }
-		    catch(InterruptedException success) {
-                    }
-		}
-	    });
-
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            t.interrupt();
-            t.join(SHORT_DELAY_MS);
-            assertFalse(t.isAlive());
-        }
-        catch (Exception ex) {
-            unexpectedException();
-        }
+        final CountDownLatch locked = new CountDownLatch(1);
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.writeLock().lock();
+                assertTrue(lock.isWriteLocked());
+                assertTrue(lock.isWriteLockedByCurrentThread());
+                assertHasNoWaiters(lock, c);
+                locked.countDown();
+                try {
+                    c.awaitNanos(MILLISECONDS.toNanos(LONG_DELAY_MS));
+                } finally {
+                    assertTrue(lock.isWriteLocked());
+                    assertTrue(lock.isWriteLockedByCurrentThread());
+                    assertHasNoWaiters(lock, c);
+                    lock.writeLock().unlock();
+                    assertFalse(Thread.interrupted());
+                }
+            }});
+
+        locked.await();
+        assertHasWaiters(lock, c, t);
+        t.interrupt();
+        awaitTermination(t);
+        assertFalse(lock.isWriteLocked());
     }
 
     /**
      * awaitUntil is interruptible
      */
-    public void testAwaitUntil_Interrupt() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();	
+    public void testAwaitUntil_Interrupt() throws InterruptedException {
+        final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();
         final Condition c = lock.writeLock().newCondition();
-	Thread t = new Thread(new Runnable() { 
-		public void run() {
-		    try {
-			lock.writeLock().lock();
-                        java.util.Date d = new java.util.Date();
-                        c.awaitUntil(new java.util.Date(d.getTime() + 10000));
-                        lock.writeLock().unlock();
-                        threadShouldThrow();
-		    }
-		    catch(InterruptedException success) {
-                    }
-		}
-	    });
-
-        try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            t.interrupt();
-            t.join(SHORT_DELAY_MS);
-            assertFalse(t.isAlive());
-        }
-        catch (Exception ex) {
-            unexpectedException();
-        }
+        final CountDownLatch locked = new CountDownLatch(1);
+        Thread t = newStartedThread(new CheckedInterruptedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.writeLock().lock();
+                assertTrue(lock.isWriteLocked());
+                assertTrue(lock.isWriteLockedByCurrentThread());
+                assertHasNoWaiters(lock, c);
+                locked.countDown();
+                java.util.Date d = new java.util.Date();
+                try {
+                    c.awaitUntil(new java.util.Date(d.getTime() + 10000));
+                } finally {
+                    assertTrue(lock.isWriteLocked());
+                    assertTrue(lock.isWriteLockedByCurrentThread());
+                    assertHasNoWaiters(lock, c);
+                    lock.writeLock().unlock();
+                    assertFalse(Thread.interrupted());
+                }
+            }});
+
+        locked.await();
+        assertHasWaiters(lock, c, t);
+        t.interrupt();
+        awaitTermination(t);
+        assertFalse(lock.isWriteLocked());
     }
 
     /**
      * signalAll wakes up all threads
      */
-    public void testSignalAll() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();	
+    public void testSignalAll() throws InterruptedException {
+        final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();
         final Condition c = lock.writeLock().newCondition();
-	Thread t1 = new Thread(new Runnable() { 
-		public void run() {
-		    try {
-			lock.writeLock().lock();
-                        c.await();
-                        lock.writeLock().unlock();
-		    }
-		    catch(InterruptedException e) {
-                        threadUnexpectedException();
-                    }
-		}
-	    });
-
-	Thread t2 = new Thread(new Runnable() { 
-		public void run() {
-		    try {
-			lock.writeLock().lock();
-                        c.await();
-                        lock.writeLock().unlock();
-		    }
-		    catch(InterruptedException e) {
-                        threadUnexpectedException();
-                    }
-		}
-	    });
+        final CountDownLatch locked = new CountDownLatch(2);
+        final Lock writeLock = lock.writeLock();
+        Thread t1 = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                writeLock.lock();
+                locked.countDown();
+                c.await();
+                writeLock.unlock();
+            }});
+
+        Thread t2 = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                writeLock.lock();
+                locked.countDown();
+                c.await();
+                writeLock.unlock();
+            }});
+
+        locked.await();
+        writeLock.lock();
+        assertHasWaiters(lock, c, t1, t2);
+        c.signalAll();
+        assertHasNoWaiters(lock, c);
+        writeLock.unlock();
+        awaitTermination(t1);
+        awaitTermination(t2);
+    }
 
-        try {
-            t1.start();
-            t2.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            lock.writeLock().lock();
-            c.signalAll();
-            lock.writeLock().unlock();
-            t1.join(SHORT_DELAY_MS);
-            t2.join(SHORT_DELAY_MS);
-            assertFalse(t1.isAlive());
-            assertFalse(t2.isAlive());
-        }
-        catch (Exception ex) {
-            unexpectedException();
-        }
+    /**
+     * signal wakes up waiting threads in FIFO order.
+     */
+    public void testSignalWakesFifo() throws InterruptedException {
+        final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();
+        final Condition c = lock.writeLock().newCondition();
+        final CountDownLatch locked1 = new CountDownLatch(1);
+        final CountDownLatch locked2 = new CountDownLatch(1);
+        final Lock writeLock = lock.writeLock();
+        Thread t1 = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                writeLock.lock();
+                locked1.countDown();
+                c.await();
+                writeLock.unlock();
+            }});
+
+        locked1.await();
+
+        Thread t2 = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                writeLock.lock();
+                locked2.countDown();
+                c.await();
+                writeLock.unlock();
+            }});
+
+        locked2.await();
+
+        writeLock.lock();
+        assertHasWaiters(lock, c, t1, t2);
+        assertFalse(lock.hasQueuedThreads());
+        c.signal();
+        assertHasWaiters(lock, c, t2);
+        assertTrue(lock.hasQueuedThread(t1));
+        assertFalse(lock.hasQueuedThread(t2));
+        c.signal();
+        assertHasNoWaiters(lock, c);
+        assertTrue(lock.hasQueuedThread(t1));
+        assertTrue(lock.hasQueuedThread(t2));
+        writeLock.unlock();
+        awaitTermination(t1);
+        awaitTermination(t2);
     }
 
     /**
      * A serialized lock deserializes as unlocked
      */
-    public void testSerialization() {
+    public void testSerialization() throws Exception {
         ReentrantReadWriteLock l = new ReentrantReadWriteLock();
         l.readLock().lock();
         l.readLock().unlock();
 
+        ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
+        ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
+        out.writeObject(l);
+        out.close();
+
+        ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
+        ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
+        ReentrantReadWriteLock r = (ReentrantReadWriteLock) in.readObject();
+        r.readLock().lock();
+        r.readLock().unlock();
+    }
+
+    /**
+     * hasQueuedThreads reports whether there are waiting threads
+     */
+    public void testhasQueuedThreads() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
+        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
+        assertFalse(lock.hasQueuedThreads());
+        lock.writeLock().lock();
+        assertFalse(lock.hasQueuedThreads());
+        long startTime = System.nanoTime();
+        t1.start();
+        waitForQueuedThread(lock, t1);
+        t2.start();
+        waitForQueuedThread(lock, t2);
+        assertTrue(lock.hasQueuedThreads());
+        t1.interrupt();
+        awaitTermination(t1);
+        assertTrue(lock.hasQueuedThreads());
+        lock.writeLock().unlock();
+        awaitTermination(t2);
+        assertFalse(lock.hasQueuedThreads());
+    }
+
+    /**
+     * hasQueuedThread(null) throws NPE
+     */
+    public void testHasQueuedThreadNPE() {
+        final ReentrantReadWriteLock sync = new ReentrantReadWriteLock();
         try {
-            ByteArrayOutputStream bout = new ByteArrayOutputStream(10000);
-            ObjectOutputStream out = new ObjectOutputStream(new BufferedOutputStream(bout));
-            out.writeObject(l);
-            out.close();
-
-            ByteArrayInputStream bin = new ByteArrayInputStream(bout.toByteArray());
-            ObjectInputStream in = new ObjectInputStream(new BufferedInputStream(bin));
-            ReentrantReadWriteLock r = (ReentrantReadWriteLock) in.readObject();
-            r.readLock().lock();
-            r.readLock().unlock();
-        } catch(Exception e){
-            e.printStackTrace();
-            unexpectedException();
-        }
+            sync.hasQueuedThread(null);
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
+
+    /**
+     * hasQueuedThread reports whether a thread is queued.
+     */
+    public void testHasQueuedThread() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        Thread t1 = new Thread(new InterruptedLockRunnable(lock));
+        Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
+        assertFalse(lock.hasQueuedThread(t1));
+        assertFalse(lock.hasQueuedThread(t2));
+        lock.writeLock().lock();
+        long startTime = System.nanoTime();
+        t1.start();
+        waitForQueuedThread(lock, t1);
+        assertTrue(lock.hasQueuedThread(t1));
+        assertFalse(lock.hasQueuedThread(t2));
+        t2.start();
+        waitForQueuedThread(lock, t2);
+        assertTrue(lock.hasQueuedThread(t1));
+        assertTrue(lock.hasQueuedThread(t2));
+        t1.interrupt();
+        awaitTermination(t1);
+        assertFalse(lock.hasQueuedThread(t1));
+        assertTrue(lock.hasQueuedThread(t2));
+        lock.writeLock().unlock();
+        awaitTermination(t2);
+        assertFalse(lock.hasQueuedThread(t1));
+        assertFalse(lock.hasQueuedThread(t2));
     }
 
     /**
      * getQueueLength reports number of waiting threads
      */
-    public void testGetQueueLength() { 
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+    public void testGetQueueLength() throws InterruptedException {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
         Thread t1 = new Thread(new InterruptedLockRunnable(lock));
         Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
-        try {
-            assertEquals(0, lock.getQueueLength());
-            lock.writeLock().lock();
-            t1.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            assertEquals(1, lock.getQueueLength());
-            t2.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            assertEquals(2, lock.getQueueLength());
-            t1.interrupt();
-            Thread.sleep(SHORT_DELAY_MS);
-            assertEquals(1, lock.getQueueLength());
-            lock.writeLock().unlock();
-            Thread.sleep(SHORT_DELAY_MS);
-            assertEquals(0, lock.getQueueLength());
-            t1.join();
-            t2.join();
-        } catch(Exception e){
-            unexpectedException();
-        }
-    } 
+        assertEquals(0, lock.getQueueLength());
+        lock.writeLock().lock();
+        long startTime = System.nanoTime();
+        t1.start();
+        waitForQueuedThread(lock, t1);
+        assertEquals(1, lock.getQueueLength());
+        t2.start();
+        waitForQueuedThread(lock, t2);
+        assertEquals(2, lock.getQueueLength());
+        t1.interrupt();
+        awaitTermination(t1);
+        assertEquals(1, lock.getQueueLength());
+        lock.writeLock().unlock();
+        awaitTermination(t2);
+        assertEquals(0, lock.getQueueLength());
+    }
 
     /**
      * getQueuedThreads includes waiting threads
      */
-    public void testGetQueuedThreads() { 
-	final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();
+    public void testGetQueuedThreads() throws InterruptedException {
+        final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();
         Thread t1 = new Thread(new InterruptedLockRunnable(lock));
         Thread t2 = new Thread(new InterruptibleLockRunnable(lock));
+        assertTrue(lock.getQueuedThreads().isEmpty());
+        lock.writeLock().lock();
+        long startTime = System.nanoTime();
+        assertTrue(lock.getQueuedThreads().isEmpty());
+        t1.start();
+        waitForQueuedThread(lock, t1);
+        assertEquals(1, lock.getQueuedThreads().size());
+        assertTrue(lock.getQueuedThreads().contains(t1));
+        t2.start();
+        waitForQueuedThread(lock, t2);
+        assertEquals(2, lock.getQueuedThreads().size());
+        assertTrue(lock.getQueuedThreads().contains(t1));
+        assertTrue(lock.getQueuedThreads().contains(t2));
+        t1.interrupt();
+        awaitTermination(t1);
+        assertFalse(lock.getQueuedThreads().contains(t1));
+        assertTrue(lock.getQueuedThreads().contains(t2));
+        assertEquals(1, lock.getQueuedThreads().size());
+        lock.writeLock().unlock();
+        awaitTermination(t2);
+        assertTrue(lock.getQueuedThreads().isEmpty());
+    }
+
+    /**
+     * hasWaiters throws NPE if null
+     */
+    public void testHasWaitersNPE() {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
         try {
-            assertTrue(lock.getQueuedThreads().isEmpty());
-            lock.writeLock().lock();
-            assertTrue(lock.getQueuedThreads().isEmpty());
-            t1.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            assertTrue(lock.getQueuedThreads().contains(t1));
-            t2.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            assertTrue(lock.getQueuedThreads().contains(t1));
-            assertTrue(lock.getQueuedThreads().contains(t2));
-            t1.interrupt();
-            Thread.sleep(SHORT_DELAY_MS);
-            assertFalse(lock.getQueuedThreads().contains(t1));
-            assertTrue(lock.getQueuedThreads().contains(t2));
-            lock.writeLock().unlock();
-            Thread.sleep(SHORT_DELAY_MS);
-            assertTrue(lock.getQueuedThreads().isEmpty());
-            t1.join();
-            t2.join();
-        } catch(Exception e){
-            unexpectedException();
-        }
-    } 
+            lock.hasWaiters(null);
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
 
     /**
-     * hasWaiters returns true when a thread is waiting, else false
+     * getWaitQueueLength throws NPE if null
      */
-    public void testHasWaiters() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();	
-        final AbstractReentrantLock.ConditionObject c = (AbstractReentrantLock.ConditionObject)(lock.writeLock().newCondition());
-	Thread t = new Thread(new Runnable() { 
-		public void run() {
-		    try {
-			lock.writeLock().lock();
-                        threadAssertFalse(c.hasWaiters());
-                        threadAssertEquals(0, c.getWaitQueueLength());
-                        c.await();
-                        lock.writeLock().unlock();
-		    }
-		    catch(InterruptedException e) {
-                        threadUnexpectedException();
-                    }
-		}
-	    });
+    public void testGetWaitQueueLengthNPE() {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        try {
+            lock.getWaitQueueLength(null);
+            shouldThrow();
+        } catch (NullPointerException success) {}
+    }
 
+    /**
+     * getWaitingThreads throws NPE if null
+     */
+    public void testGetWaitingThreadsNPE() {
+        final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();
         try {
-            t.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            lock.writeLock().lock();
-            assertTrue(c.hasWaiters());
-            assertEquals(1, c.getWaitQueueLength());
-            c.signal();
-            lock.writeLock().unlock();
-            Thread.sleep(SHORT_DELAY_MS);
-            lock.writeLock().lock();
-            assertFalse(c.hasWaiters());
-            assertEquals(0, c.getWaitQueueLength());
-            lock.writeLock().unlock();
-            t.join(SHORT_DELAY_MS);
-            assertFalse(t.isAlive());
-        }
-        catch (Exception ex) {
-            unexpectedException();
-        }
+            lock.getWaitingThreads(null);
+            shouldThrow();
+        } catch (NullPointerException success) {}
     }
 
     /**
-     * getWaitQueueLength returns number of waiting threads
+     * hasWaiters throws IAE if not owned
      */
-    public void testGetWaitQueueLength() {
-	final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();	
-        final AbstractReentrantLock.ConditionObject c = (AbstractReentrantLock.ConditionObject)(lock.writeLock().newCondition());
-	Thread t1 = new Thread(new Runnable() { 
-		public void run() {
-		    try {
-			lock.writeLock().lock();
-                        threadAssertFalse(c.hasWaiters());
-                        threadAssertEquals(0, c.getWaitQueueLength());
-                        c.await();
-                        lock.writeLock().unlock();
-		    }
-		    catch(InterruptedException e) {
-                        threadUnexpectedException();
-                    }
-		}
-	    });
-
-	Thread t2 = new Thread(new Runnable() { 
-		public void run() {
-		    try {
-			lock.writeLock().lock();
-                        threadAssertTrue(c.hasWaiters());
-                        threadAssertEquals(1, c.getWaitQueueLength());
-                        c.await();
-                        lock.writeLock().unlock();
-		    }
-		    catch(InterruptedException e) {
-                        threadUnexpectedException();
-                    }
-		}
-	    });
+    public void testHasWaitersIAE() {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        final Condition c = lock.writeLock().newCondition();
+        final ReentrantReadWriteLock lock2 = new ReentrantReadWriteLock();
+        try {
+            lock2.hasWaiters(c);
+            shouldThrow();
+        } catch (IllegalArgumentException success) {}
+    }
 
+    /**
+     * hasWaiters throws IMSE if not locked
+     */
+    public void testHasWaitersIMSE() {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        final Condition c = lock.writeLock().newCondition();
         try {
-            t1.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            t2.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            lock.writeLock().lock();
-            assertTrue(c.hasWaiters());
-            assertEquals(2, c.getWaitQueueLength());
-            c.signalAll();
-            lock.writeLock().unlock();
-            Thread.sleep(SHORT_DELAY_MS);
-            lock.writeLock().lock();
-            assertFalse(c.hasWaiters());
-            assertEquals(0, c.getWaitQueueLength());
-            lock.writeLock().unlock();
-            t1.join(SHORT_DELAY_MS);
-            t2.join(SHORT_DELAY_MS);
-            assertFalse(t1.isAlive());
-            assertFalse(t2.isAlive());
-        }
-        catch (Exception ex) {
-            unexpectedException();
-        }
+            lock.hasWaiters(c);
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
     }
 
     /**
-     * getWaitingThreads returns only and all waiting threads
+     * getWaitQueueLength throws IAE if not owned
      */
-    public void testGetWaitingThreads() {
-	final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();	
-        final PublicReentrantReadWriteLock.PublicCondition c = (PublicReentrantReadWriteLock.PublicCondition)lock.newCondition();
-	Thread t1 = new Thread(new Runnable() { 
-		public void run() {
-		    try {
-			lock.writeLock().lock();
-                        threadAssertTrue(c.getWaitingThreads().isEmpty());
-                        c.await();
-                        lock.writeLock().unlock();
-		    }
-		    catch(InterruptedException e) {
-                        threadUnexpectedException();
-                    }
-		}
-	    });
-
-	Thread t2 = new Thread(new Runnable() { 
-		public void run() {
-		    try {
-			lock.writeLock().lock();
-                        threadAssertFalse(c.getWaitingThreads().isEmpty());
-                        c.await();
-                        lock.writeLock().unlock();
-		    }
-		    catch(InterruptedException e) {
-                        threadUnexpectedException();
-                    }
-		}
-	    });
+    public void testGetWaitQueueLengthIAE() {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        final Condition c = lock.writeLock().newCondition();
+        final ReentrantReadWriteLock lock2 = new ReentrantReadWriteLock();
+        try {
+            lock2.getWaitQueueLength(c);
+            shouldThrow();
+        } catch (IllegalArgumentException success) {}
+    }
 
+    /**
+     * getWaitQueueLength throws IMSE if not locked
+     */
+    public void testGetWaitQueueLengthIMSE() {
+        final ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        final Condition c = lock.writeLock().newCondition();
         try {
-            lock.writeLock().lock();
-            assertTrue(c.getWaitingThreads().isEmpty());
-            lock.writeLock().unlock();
-            t1.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            t2.start();
-            Thread.sleep(SHORT_DELAY_MS);
-            lock.writeLock().lock();
-            assertTrue(c.hasWaiters());
-            assertTrue(c.getWaitingThreads().contains(t1));
-            assertTrue(c.getWaitingThreads().contains(t2));
-            c.signalAll();
-            lock.writeLock().unlock();
-            Thread.sleep(SHORT_DELAY_MS);
-            lock.writeLock().lock();
-            assertFalse(c.hasWaiters());
-            assertTrue(c.getWaitingThreads().isEmpty());
-            lock.writeLock().unlock();
-            t1.join(SHORT_DELAY_MS);
-            t2.join(SHORT_DELAY_MS);
-            assertFalse(t1.isAlive());
-            assertFalse(t2.isAlive());
-        }
-        catch (Exception ex) {
-            unexpectedException();
-        }
+            lock.getWaitQueueLength(c);
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
+    }
+
+    /**
+     * getWaitingThreads throws IAE if not owned
+     */
+    public void testGetWaitingThreadsIAE() {
+        final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();
+        final Condition c = lock.writeLock().newCondition();
+        final PublicReentrantReadWriteLock lock2 = new PublicReentrantReadWriteLock();
+        try {
+            lock2.getWaitingThreads(c);
+            shouldThrow();
+        } catch (IllegalArgumentException success) {}
+    }
+
+    /**
+     * getWaitingThreads throws IMSE if not locked
+     */
+    public void testGetWaitingThreadsIMSE() {
+        final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();
+        final Condition c = lock.writeLock().newCondition();
+        try {
+            lock.getWaitingThreads(c);
+            shouldThrow();
+        } catch (IllegalMonitorStateException success) {}
+    }
+
+    /**
+     * hasWaiters returns true when a thread is waiting, else false
+     */
+    public void testHasWaiters() throws InterruptedException {
+        final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();
+        final Condition c = lock.writeLock().newCondition();
+        final CountDownLatch locked = new CountDownLatch(1);
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.writeLock().lock();
+                assertFalse(lock.hasWaiters(c));
+                locked.countDown();
+                assertEquals(0, lock.getWaitQueueLength(c));
+                c.await();
+                lock.writeLock().unlock();
+            }});
+
+        locked.await();
+        lock.writeLock().lock();
+        assertTrue(lock.hasWaiters(c));
+        assertEquals(1, lock.getWaitQueueLength(c));
+        c.signal();
+        assertHasNoWaiters(lock, c);
+        lock.writeLock().unlock();
+        awaitTermination(t);
+        assertHasNoWaiters(lock, c);
+    }
+
+    /**
+     * getWaitQueueLength returns number of waiting threads
+     */
+    public void testGetWaitQueueLength() throws InterruptedException {
+        final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();
+        final Condition c = lock.writeLock().newCondition();
+        final CountDownLatch locked = new CountDownLatch(1);
+        Thread t = newStartedThread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.writeLock().lock();
+                assertEquals(0, lock.getWaitQueueLength(c));
+                locked.countDown();
+                c.await();
+                lock.writeLock().unlock();
+            }});
+
+        locked.await();
+        lock.writeLock().lock();
+        assertHasWaiters(lock, c, t);
+        assertEquals(1, lock.getWaitQueueLength(c));
+        c.signal();
+        assertHasNoWaiters(lock, c);
+        assertEquals(0, lock.getWaitQueueLength(c));
+        lock.writeLock().unlock();
+        awaitTermination(t);
+    }
+
+    /**
+     * getWaitingThreads returns only and all waiting threads
+     */
+    public void testGetWaitingThreads() throws InterruptedException {
+        final PublicReentrantReadWriteLock lock = new PublicReentrantReadWriteLock();
+        final Condition c = lock.writeLock().newCondition();
+        final CountDownLatch locked1 = new CountDownLatch(1);
+        final CountDownLatch locked2 = new CountDownLatch(1);
+        Thread t1 = new Thread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.writeLock().lock();
+                assertTrue(lock.getWaitingThreads(c).isEmpty());
+                locked1.countDown();
+                c.await();
+                lock.writeLock().unlock();
+            }});
+
+        Thread t2 = new Thread(new CheckedRunnable() {
+            public void realRun() throws InterruptedException {
+                lock.writeLock().lock();
+                assertFalse(lock.getWaitingThreads(c).isEmpty());
+                locked2.countDown();
+                c.await();
+                lock.writeLock().unlock();
+            }});
+
+        lock.writeLock().lock();
+        assertTrue(lock.getWaitingThreads(c).isEmpty());
+        lock.writeLock().unlock();
+
+        t1.start();
+        locked1.await();
+        t2.start();
+        locked2.await();
+
+        lock.writeLock().lock();
+        assertTrue(lock.hasWaiters(c));
+        assertTrue(lock.getWaitingThreads(c).contains(t1));
+        assertTrue(lock.getWaitingThreads(c).contains(t2));
+        assertEquals(2, lock.getWaitingThreads(c).size());
+        c.signalAll();
+        assertHasNoWaiters(lock, c);
+        lock.writeLock().unlock();
+
+        awaitTermination(t1);
+        awaitTermination(t2);
+
+        assertHasNoWaiters(lock, c);
+    }
+
+    /**
+     * toString indicates current lock state
+     */
+    public void testToString() {
+        ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        String us = lock.toString();
+        assertTrue(us.indexOf("Write locks = 0") >= 0);
+        assertTrue(us.indexOf("Read locks = 0") >= 0);
+        lock.writeLock().lock();
+        String ws = lock.toString();
+        assertTrue(ws.indexOf("Write locks = 1") >= 0);
+        assertTrue(ws.indexOf("Read locks = 0") >= 0);
+        lock.writeLock().unlock();
+        lock.readLock().lock();
+        lock.readLock().lock();
+        String rs = lock.toString();
+        assertTrue(rs.indexOf("Write locks = 0") >= 0);
+        assertTrue(rs.indexOf("Read locks = 2") >= 0);
+    }
+
+    /**
+     * readLock.toString indicates current lock state
+     */
+    public void testReadLockToString() {
+        ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        String us = lock.readLock().toString();
+        assertTrue(us.indexOf("Read locks = 0") >= 0);
+        lock.readLock().lock();
+        lock.readLock().lock();
+        String rs = lock.readLock().toString();
+        assertTrue(rs.indexOf("Read locks = 2") >= 0);
+    }
+
+    /**
+     * writeLock.toString indicates current lock state
+     */
+    public void testWriteLockToString() {
+        ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
+        String us = lock.writeLock().toString();
+        assertTrue(us.indexOf("Unlocked") >= 0);
+        lock.writeLock().lock();
+        String ls = lock.writeLock().toString();
+        assertTrue(ls.indexOf("Locked") >= 0);
     }
 
 }