How does Java's PriorityQueue differ from a min-heap?

Question

Why did they name PriorityQueue if you can't insertWithPriority? It seems very similar to a heap. Are there any differences? If no difference, then why was it named PriorityQueue and not Heap?

Answer 1

The default PriorityQueue is implemented with Min-Heap, that is the top element is the minimum one in the heap.

In order to implement a max-heap, you can create your own Comparator:

import java.util.Comparator;  public class MyComparator implements Comparator<Integer> {     public int compare( Integer x, Integer y )     {         return y - x;     } } 

So, you can create a min-heap and max-heap in the following way:

PriorityQueue minHeap=new PriorityQueue(); PriorityQueue maxHeap=new PriorityQueue(size, new MyComparator()); 

Answer 2

For max-heap you can use:

PriorityQueue<Integer> queue = new PriorityQueue<>(10, Collections.reverseOrder());