Deadlocks

• Not enough to synchronize add, remove
• if (!queue.isFull()) queue.add(...);  
  can still be interrupted
• Must move test inside add method
  

  public synchronized void add(E newValue)
  {
     . . .
     try
     {
        while (queue is full)
           wait for more space
        . . .
     }
     finally { ... }
  }
  

• Problem: nobody else can call remove