/**
   * A Throwable used to record a stack trace that illustrates an example of a specific lock
   * acquisition ordering. The top of the stack trace is truncated such that it starts with the
   * acquisition of the lock in question, e.g.
   *
   * <pre>
   * com...ExampleStackTrace: LockB -&gt; LockC
   *   at com...CycleDetectingReentrantLock.lock(CycleDetectingLockFactory.java:443)
   *   at ...
   *   at ...

 * </ul>
 *
 * <p>A common alternative to using this class is to find or create a suitable <a
 * href="http://en.wikipedia.org/wiki/Null_Object_pattern">null object</a> for the type in question.
 *
 * <p>This class is not intended as a direct analogue of any existing "option" or "maybe" construct
 * from other programming environments, though it may bear some similarities.
 *