code: private boolean tryLock()
    {
      if (tc.isEntryEnabled())
        SibTr.entry(tc, "tryLock", this);
  
      boolean result = false;
  
      synchronized (iMutex)
      {
        // Check that we aren't exclusively locked.
        if (!iExclusivelyLocked || iExclusiveLockHolder == Thread.currentThread())
        {
          incrementThreadLockCount();
          result = true;
        }      
      }
  
      if (tc.isEntryEnabled())
        SibTr.exit(tc, "tryLock", new Boolean(result));
  
      return result;
    }
docs: This method increments a the number of locks that have
  been obtained.
  
  If the thread requesting the lock happens to be the thread
  that already has the exclusive lock we let that succeed as
  we don't want to cause any dead locks !
  
  @return boolean  if the lock was achieved.