SE450: Exceptions in the Contract [50/57]

/**
   . . .
   @throws NoSuchElementException if queue is empty
*/
public Message remove() 
{ 
   if (count == 0) 
      throw new NoSuchElementException();
   Message r = elements[head]; 
   . . .
} 

• Exception throw part of the contract
• Caller can rely on behavior
• Exception throw not result of precondition violation
• This method has no precondition