Priority Queue Clarification

[Muthaiah Ramanathan]

I'm puzzled with the behaviour of the PriorityQueue. The executing the following code

 
PriorityQueue<Integer> q = new PriorityQueue<Integer> ();
q.offer(5);
q.offer(1);
q.offer(2);
q.offer(3);
q.offer(0);
q.offer(7);
q.offer(9);
System.out.println(q);

prints out [0, 1, 2, 7, 5, 9, 3]

In the SUN API Definition, it says

An unbounded priority queue based on a priority heap. This queue orders elements according to an order specified at construction time, which is specified either according to their natural order (see Comparable), or according to a Comparator, depending on which constructor is used.

But why is the above not sorted according to the natural order? Or is it just the way the toString works?

[Muthaiah Ramanathan]

BTW - changing it to String also results in the same.

PriorityQueue<String> q = new PriorityQueue<String> ();
q.offer("5");
q.offer("1");
q.offer("2");
q.offer("3");
q.offer("0");
q.offer("7");
q.offer("9");
System.out.println(q);

[Ankit Garg]

This problem has been asked multiple times. See this or this...

[Brij Garg]

But why is the above not sorted according to the natural order? Or is it just the way the toString works?

This is the natural order only.

[Muthaiah Ramanathan]

Oh Ok. Thanks Ankit. I wonder why sun didn't mention this clearly.

BTW - I did search for Priority queue before posting a new thread and didn't find these threads!