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Set containsAll() Method in Java

Last Updated : 11 Jul, 2025
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The containsAll() method of Set in Java is used to check if a collection contains all the elements of a specified collection. This method is part of the Collection interface.

Example 1: This example checks if all elements of one set are present in another set and it will return true if they are identical.

Java 
// Java program to demonstrates 
// the working of containsAll() method
import java.util.*;

class Geeks {
    public static void main(String args[])
    {
        // Creating an empty set
        Set<String> s1 = new HashSet<String>();

        // Use add() method to
        // add elements in the set
        s1.add("Java");
        s1.add("C++");
        s1.add("Python");

        System.out.println("Set 1: " + s1);

        // Creating another empty set
        Set<String> s2 = new HashSet<String>();

        // Use add() method to
        // add elements in the set
        s2.add("Java");
        s2.add("C++");
        s2.add("Python");

        System.out.println("Set 2: " + s2);

        // Check if the set
        // contains same elements
        System.out.println("Does set 1 contains set 2?: "
                           + s1.containsAll(s2));
    }
}

Output
Set 1: [Java, C++, Python]
Set 2: [Java, C++, Python]
Does set 1 contains set 2?: true

Syntax of containsAll() Method

boolean containsAll(Collection<?> c)

  • Parameter: "c" is the collection whose elements are to be checked in the current collection.
  • Return Type: This method returns "true" if the current collection contains all the elements of the specified collection, otherwise returns "false".

Example 2: This example checks if all elements of one set are present in another set and it will return false if they are not identical.

Java 
// Java program to demonstrates that 
// containsALl() method returns false
import java.util.*;

class Geeks {
  
    public static void main(String args[]) {

        // Creating an empty s1
        Set<String> s1 = new HashSet<String>();

        // Use add() method to add elements in s1
        s1.add("Java");
        s1.add("C++");
        s1.add("Python");

        System.out.println("Set 1: " + s1);

        // Creating another empty s2
        Set<String> s2 = new HashSet<String>();

        // Use add() method to add elements in s2
        s2.add("10");
        s2.add("20");

        System.out.println("Set 2: " + s2);

        // Check if s1 contains all elements of s2
        System.out.println("Does s1 contain all elements of s2: " 
                           + s1.containsAll(s2));
    }
}

Output
Set 1: [Java, C++, Python]
Set 2: [20, 10]
Does s1 contain all elements of s2: false

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