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Java Collections - ArrayDeque.push() Examples

Java Collections Java Java API

Class:

java.util.ArrayDeque

Method:

public void push(E e)

Inserts the element at the front of this deque.

This method is equivalent to addFirst().

Examples

package com.logicbig.example.arraydeque;

import java.util.ArrayDeque;

public class PushExample {

    public static void main(String... args) {
        ArrayDeque<Integer> ad = new ArrayDeque<>();
        ad.push(3);
        System.out.println(ad);
    }
}

Output

[3]

package com.logicbig.example.arraydeque;

import java.util.ArrayDeque;

public class PushExample2 {

    public static void main(String... args) {
        ArrayDeque<Integer> ad = new ArrayDeque<>();
        ad.push(null);
    }
}

Output

Caused by: java.lang.NullPointerException
	at java.base/java.util.ArrayDeque.addFirst(ArrayDeque.java:287)
	at java.base/java.util.ArrayDeque.push(ArrayDeque.java:576)
	at com.logicbig.example.arraydeque.PushExample2.main(PushExample2.java:14)
	... 6 more

See Also