What is the ArrayList.containsAll() method in Java?

The ArrayList.containsAll() method in Java is used to check if the list contains all the elements present in a collection.

Syntax

The ArrayList.containsAll() method in Java can be declared as shown in the code snippet below:

boolean containsAll(Collection c)

c: The collection whose elements will be checked if they are present in the list.

Return value

The ArrayList.containsAll() method returns a boolean, such that:

The return value is true if the list contains all the elements present in the collection c.
The return value is false if the list does not contain all the elements present in the collection c.

Note: If the collection is null, the ArrayList.containsAll() method throws the NullPointerException.

Examples

Example 1

Consider the code snippet below, which demonstrates the use of the ArrayList.containsAll() method.

import java.util.*;
  
public class Example1 {
    public static void main(String args[])
    {
        List<String> list1 = new ArrayList<String>();
        list1.add("Hello");
        list1.add("world");
        list1.add("!");
        System.out.println("list1: " + list1);
  
        List<String> list2 = new ArrayList<String>();
        list2.add("Hello");
        list2.add("world2");
        System.out.println("list2: " + list2);
  
        System.out.println("list1.containsAll(): " + list1.containsAll(list2));
    }
}

import java.util.*;
  
public class Example2 {
    public static void main(String args[])
    {
        List<String> list1 = new ArrayList<String>();
        list1.add("Hello");
        list1.add("world");
        list1.add("!");
        System.out.println("list1: " + list1);
  
        List<String> list2 = new ArrayList<String>();
        list2.add("Hello");
        list2.add("world");
        System.out.println("list2: " + list2);
  
        System.out.println("list1.containsAll(): " + list1.containsAll(list2));
    }
}