Set containsAll() Method in Java

Last Updated : 05 Feb, 2025

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

Set hashCode() Method in Java

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