PriorityQueue sorting weirdness

priority-queue-sorting-weirdness.java

System.err.println(new PriorityQueue<Integer>(Arrays.asList(3, 1, 2)));
// Prints: [1, 3, 2]

System.err.println(new TreeSet<Integer>(Arrays.asList(3, 1, 2)));
// Prints: [1, 2, 3]

/*
This is due to PriorityQueue's Iterator. From the javadoc:
"...Iterator provided in method iterator() is not guaranteed to
traverse the elements of the priority queue in any particular order...".

PriorityQueue.toString() is in reality AbstractCollection.toString()
which uses the iterator of the subclass to print the elements.
*/