Stack push() Method in Java (original) (raw)

Last Updated : 10 Jun, 2022

Java.util.Stack.push(E element) method is used to push an element into the Stack. The element gets pushed onto the top of the Stack.

Syntax:

STACK.push(E element)

Parameters: The method accepts one parameter element of type Stack and refers to the element to be pushed into the stack.

Return Value: The method returns the argument passed. It also accepts the null value unlike ArrayDeque.push() which throws java.lang.NullPointerException on doing the same.

Below programs illustrate the Java.util.Stack.push() method:

Program 1: Adding String elements into the Stack.

Java

import java.util.*;

public class StackDemo {

`` public static void main(String args[])

`` {

`` Stack& lt;

`` String& gt;

`` STACK = new Stack& lt;

`` String& gt;

`` ();

`` STACK.push(" Welcome & quot;);

`` STACK.push(" To & quot;);

`` STACK.push(" Geeks & quot;);

`` STACK.push(" For & quot;);

`` STACK.push(" Geeks & quot;);

`` System.out.println(" Initial Stack

`` : "

`` + STACK);

`` STACK.push(" Hello & quot;);

`` STACK.push(" World & quot;);

`` System.out.println(" Final Stack

`` : "

`` + STACK);

`` }

}

Output:

Initial Stack: [Welcome, To, Geeks, For, Geeks] Final Stack: [Welcome, To, Geeks, For, Geeks, Hello, World]

Program 2: Adding Integer elements into the Stack.

Java

import java.util.*;

public class StackDemo {

`` public static void main(String args[])

`` {

`` Stack<Integer> STACK = new Stack<Integer>();

`` STACK.push( 10 );

`` STACK.push( 15 );

`` STACK.push( 30 );

`` STACK.push( 20 );

`` STACK.push( 5 );

`` STACK.push( null );

`` System.out.println("Initial Stack: " + STACK);

`` STACK.push( 1254 );

`` STACK.push( 4521 );

`` System.out.println("Final Stack: " + STACK);

`` }

}

Output:

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