code: public synchronized void post()
     {
      if (tc.isEntryEnabled()) SibTr.entry(tc, "post", ""+count);
        --count;
        if (count >= 0)
           notify();
      if (tc.isEntryEnabled()) SibTr.exit(tc, "post");
     }
docs: Post the semaphore waking up at most one waiter.  If there are no
  waiters, then the next thread issuing a waitOn call will not be
  suspended.  In fact, if post is invoked 'n' times then the next
  'n' waitOn calls will not block.
  @see Semaphore#waitOn()