Java Collections - ArrayDeque.removeFirst() Examples

Class:

java.util.ArrayDeque

Method:

public E removeFirst()

Retrieves and removes the first element of this deque. This method differs from pollFirst() only in that it throws an exception if this deque is empty.

Examples

package com.logicbig.example.arraydeque;

import java.util.ArrayDeque;
import java.util.List;

public class RemoveFirstExample {

    public static void main(String... args) {
        ArrayDeque<Integer> ad = new ArrayDeque<>(List.of(3, 8, 1));
        System.out.println(ad);
        Integer b = ad.removeFirst();
        System.out.println(b);
        System.out.println(ad);
        b = ad.removeFirst();
        System.out.println(b);
        System.out.println(ad);
    }
}

Output

[3, 8, 1]
3
[8, 1]
8
[1]

package com.logicbig.example.arraydeque;

import java.util.ArrayDeque;

public class RemoveFirstExample2 {

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

Output

Caused by: java.util.NoSuchElementException
	at java.base/java.util.ArrayDeque.removeFirst(ArrayDeque.java:359)
	at com.logicbig.example.arraydeque.RemoveFirstExample2.main(RemoveFirstExample2.java:15)
	... 6 more

Java Collections - ArrayDeque.removeFirst() Examples

Class:

Method:

Examples

Output

Output

See Also