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Java PriorityQueue poll() Method with Example

PriorityQueue Class poll() method: Here, we are going to learn about the poll() method of PriorityQueue Class with its syntax and example.
Submitted by Preeti Jain, on March 11, 2020

PriorityQueue Class poll() method

• poll() method is available in java.util package.
• poll() method is used to return the first element with removing an element from this PriorityQueue.
• poll() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• poll() method does not throw an exception at the time of returning an element.

Syntax:

    public Element poll();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of the method is Element, it returns the head element from this PriorityQueue when exists otherwise it returns null.

Example:

// Java program to demonstrate the example 
// of Element poll() method of 
// PriorityQueue

import java.util.*;

public class PollOfPriorityQueue {
    public static void main(String args[]) {
        // Instantiate PriorityQueue
        PriorityQueue < String > pq = new PriorityQueue < String > ();

        // By using add() method is add
        // the given element into priority
        // queue
        pq.add("C");
        pq.add("C++");
        pq.add("JAVA");
        pq.add("PHP");
        pq.add("ANDROID");

        // Display PriorityQueue
        System.out.println("PriorityQueue: " + pq);

        // By using poll() method is to
        // return and remove the first element
        // from this PriorityQueue
        Object ele = pq.poll();

        // Display poll element
        System.out.println("pq.poll(): " + ele);

        // Display PriorityQueue
        System.out.println("PriorityQueue: " + pq);
    }
}

Output

PriorityQueue: [ANDROID, C, JAVA, PHP, C++]
pq.poll(): ANDROID
PriorityQueue: [C, C++, JAVA, PHP]