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Java PriorityQueue comparator() Method with Example

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

PriorityQueue Class comparator() method

• comparator() method is available in java.util package.
• comparator() method is to get the Comparator object used to order the objects.
• comparator() 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.
• comparator() method does not throw an exception at the time of returning comparator.

Syntax:

    public Comparator comparator();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of the method is Comparator, it gets Comparator object used to order PriorityQueue elements otherwise it returns null when it follows default or natural sorting.

Example:

// Java program to demonstrate the example 
// of Comparator comparator() method of 
// PriorityQueue

import java.util.*;

public class ComparatorOfPriorityQueue {
    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 comparator() method is
        // used to order the priority queue
        // elements
        Comparator com = pq.comparator();

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

Output

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