ArrayDeque push() Method in Java

The Java.util.ArrayDeque.push(E element) method is used to push an element into the Deque. The operation is similar to the operation in the stack. The element gets pushed onto the top of the deque.

Syntax:

Array_Deque.push(E element)

Parameters: The parameter element is of the type ArrayDeque and refers to the element to be pushed into the deque.

Return Value: The method does not return any value.

Exceptions: The method throws NullPointerException if the passed parameter is NULL.

Below programs illustrate the Java.util.ArrayDeque.push() method:
Program 1: Adding String elements into the Deque.

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

public class ArrayDequeDemo {
    public static void main(String args[])
    {
        // Creating an empty ArrayDeque
        Deque<String> de_que = new ArrayDeque<String>();

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

        // Displaying the initial ArrayDeque
        System.out.println("Initial Deque: " + de_que);

        // Pushing elements into the deque
        de_que.push("Hello");
        de_que.push("World");

        // Displaying the final ArrayDeque
        System.out.println("Final Deque: " + de_que);
    }
}

Output:

Initial Deque: [Welcome, To, Geeks, 4, Geeks]
Final Deque: [World, Hello, Welcome, To, Geeks, 4, Geeks]

Program 2: Adding Integer elements into the Deque.

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

public class ArrayDequeDemo {
    public static void main(String args[])
    {
        // Creating an empty ArrayDeque
        Deque<Integer> de_que = new ArrayDeque<Integer>();

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

        // Displaying the initial ArrayDeque
        System.out.println("Initial Deque: " + de_que);

        // Pushing elements into the deque
        de_que.push(1254);
        de_que.push(4521);

        // Displaying the final ArrayDeque
        System.out.println("Final Deque: " + de_que);
    }
}

Output:

Initial Deque: [10, 15, 30, 20, 5]
Final Deque: [4521, 1254, 10, 15, 30, 20, 5]