Java : Priority Queue

Question

I have a java program which goes like this

public class PriorityQueueExample {

public static void main(String[] args) {
    PriorityQueue<Integer> pq = new PriorityQueue<Integer>();
    pq.add(10);
    pq.add(1);
    pq.add(9);
    pq.add(2);
    pq.add(8);
    pq.add(3);
    pq.add(7);
    pq.add(4);
    pq.add(6);
    pq.add(5);
System.out.println(pq);

}

}

My Question is why does not the priority queue sort them. As per the java specs it implements comparable and maintains the sorting order(natural sorting)

My output of the program is as follows : [1, 2, 3, 4, 5, 9, 7, 10, 6, 8]

Answer 1

It is sorted, but internally the elements are stored in a heap. If you call peek(), poll(), or remove(), you will get the right order (and that's how you access queues).