LinkedBlockingDeque peekLast() method in Java

The peekLast() method of LinkedBlockingDeque returns the last element in the Deque container, but does not deletes it. It returns null if the container is empty.

Syntax:

public E peekLast()

Parameters: This method does not accept any parameters.

Returns: This method returns last element in the Deque container if the container is not empty. It returns false if the container is empty.

Below programs illustrate peekLast() method of LinkedBlockingDeque:

Program 1:

// Java Program Demonstrate peekLast()
// method of LinkedBlockingDeque

import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;

public class GFG {
    public static void main(String[] args)

    {

        // create object of LinkedBlockingDeque
        LinkedBlockingDeque<Integer> LBD
            = new LinkedBlockingDeque<Integer>();

        // Add numbers to end of LinkedBlockingDeque
        LBD.addFirst(7855642);
        LBD.addFirst(35658786);
        LBD.addFirst(5278367);
        LBD.addFirst(74381793);

        // Print the queue
        System.out.println("Linked Blocking Deque: " + LBD);

        System.out.println("Front element in Deque: " + LBD.peekLast());
    }
}

Output:

Linked Blocking Deque: [74381793, 5278367, 35658786, 7855642]
Front element in Deque: 7855642

Program 2:

// Java Program Demonstrate peekLast()
// method of LinkedBlockingDeque
// when Deque is empty

import java.util.concurrent.LinkedBlockingDeque;
import java.util.*;

public class GFG {
    public static void main(String[] args)

    {

        // create object of LinkedBlockingDeque
        LinkedBlockingDeque<Integer> LBD
            = new LinkedBlockingDeque<Integer>();

        // Add numbers to end of LinkedBlockingDeque
        LBD.add(7855642);
        LBD.add(35658786);
        LBD.add(5278367);
        LBD.add(74381793);

        // Print the queue
        System.out.println("Linked Blocking Deque: " + LBD);

        // empty deque
        LBD.clear();

        System.out.println("Front element in Deque: " + LBD.peekLast());
    }
}

Output:

Linked Blocking Deque: [7855642, 35658786, 5278367, 74381793]
Front element in Deque: null

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/LinkedBlockingDeque.html#peekLast()