poll(), peek() and remove() Method in the Queue

String java.util.PriorityQueue.poll()

Retrieves and removes the head of this queue, or returns null if this queue is empty.

Specified by: poll() in Queue

Returns: the head of this queue, or null if this queue is empty

String java.util.PriorityQueue.peek()

Retrieves, but does not remove, the head of this queue, or returns null if this queue is empty.

Specified by: peek() in Queue

Returns: the head of this queue, or null if this queue is empty

String java.util.AbstractQueue.remove()

Retrieves and removes the head of this queue. This method differs from poll only in that it throws an exception if this queue is empty.

Specified by: remove() in Queue

Returns: the head of this queue

Throws: NoSuchElementException - if this queue is empty