PriorityQueue clear() Method in Java

The Java.util.PriorityQueue.clear() method is used to remove all the elements from a PriorityQueue. Using the clear() method only clears all the element from the queue and does not delete the queue. In other words, we can say that the clear() method is used to only empty an existing PriorityQueue.

Syntax:

Priority_Queue.clear()

Parameters: The method does not take any parameter

Return Value: The function does not returns any value.

Below programs illustrate the Java.util.PriorityQueue.clear() method:

Program 1:

// Java code to illustrate clear()
import java.util.PriorityQueue;

public class PriorityQueueDemo {
    public static void main(String args[])
    {
        // Creating an empty PriorityQueue
        PriorityQueue<String> queue = new PriorityQueue<String>();

        // Use add() method to add elements into the Queue
        queue.add("Welcome");
        queue.add("To");
        queue.add("Geeks");
        queue.add("4");
        queue.add("Geeks");

        // Displaying the PriorityQueue
        System.out.println("PriorityQueue: " + queue);

        // Clearing the PriorityQueue using clear() method
        queue.clear();

        // Displaying the final Queue after clearing;
        System.out.println("The final Queue: " + queue);
    }
}

Output:

PriorityQueue: [4, Geeks, To, Welcome, Geeks]
The final Queue: []

Program 2:

// Java code to illustrate clear()
import java.util.*;

public class PriorityQueueDemo {
    public static void main(String args[])
    {
        // Creating an empty PriorityQueue
        PriorityQueue<Integer> queue = new PriorityQueue<Integer>();

        // Use add() method to add elements into the Queue
        queue.add(10);
        queue.add(15);
        queue.add(30);
        queue.add(20);
        queue.add(5);

        // Displaying the PriorityQueue
        System.out.println("PriorityQueue: " + queue);

        // Clearing the PriorityQueue using clear() method
        queue.clear();

        // Displaying the final Queue after clearing;
        System.out.println("The final Queue: " + queue);
    }
}

Output:

PriorityQueue: [5, 10, 30, 20, 15]
The final Queue: []