PriorityQueue in Java

A PriorityQueue in Java is a queue where elements are ordered based on their priority, rather than the order of insertion. By default, it uses natural ordering (min-heap), but a custom comparator can be used to define different priorities.

• Elements are processed based on priority rather than insertion order.
• Supports standard queue operations like add(), poll(), and peek().
• Automatically grows as elements are added.
• Uses a heap data structure internally to ensure efficient insertion and removal of the highest-priority element.

Declaration of PriorityQueue

public class PriorityQueue<E> extends AbstractQueue<E> implements Serializable

where, E is the type of elements held in this queue.

import java.util.PriorityQueue;

public class Geeks 
{
    public static void main(String[] args) 
    {
      	// Priority Queue Min Type
        PriorityQueue<Integer> p = new PriorityQueue<>();

        // Add elements to the queue
        p.add(3);
        p.add(10);
        p.add(7);
        p.add(2);

        // Print the head of the queue
        System.out.println("Head of Queue: " + p.peek());
    }
}

Head of Queue: 2

Hierarchy of PriorityQueue

It implements the Queue interface which extends the Collection Interface.