HashSet contains() Method in Java

Difficulty Level : Basic
Last Updated : 26 Nov, 2018

The Java.util.HashSet.contains() method is used to check whether a specific element is present in the HashSet or not. So basically it is used to check if a Set contains any particular element.

Syntax:

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Hash_Set.contains(Object element)

Parameters: The parameter element is of the type of HashSet. This is the element that needs to be tested if it is present in the set or not.

Return Value: The method returns true if the element is present in the set else return False.

Below program illustrate the Java.util.HashSet.contains() method:

// Java code to illustrate HashSet.contains() method
import java.io.*;
import java.util.HashSet;
  
public class HashSetDemo {
    public static void main(String args[])
    {
        // Creating an empty HashSet
        HashSet<String> set = new HashSet<String>();
  
        // Using add() method to add elements into the Set
        set.add("Welcome");
        set.add("To");
        set.add("Geeks");
        set.add("4");
        set.add("Geeks");
  
        // Displaying the HashSet
        System.out.println("HashSet: " + set);
  
        // Check for "Geeks" in the set
        System.out.println("Does the Set contains 'Geeks'? " + set.contains("Geeks"));
  
        // Check for "4" in the set
        System.out.println("Does the Set contains '4'? " + set.contains("4"));
  
        // Check if the Set contains "No"
        System.out.println("Does the Set contains 'No'? " + set.contains("No"));
    }
}

Output:

HashSet: [4, Geeks, Welcome, To]
Does the Set contains 'Geeks'? true
Does the Set contains '4'? true
Does the Set contains 'No'? false

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