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Java HashSet contains() Method with Example

HashSet Class contains() method: Here, we are going to learn about the contains() method of HashSet Class with its syntax and example.
Submitted by Preeti Jain, on March 05, 2020

HashSet Class contains() method

• contains() method is available in java.util package.
• contains() method is used to check the existence of the given object (ob) in this HashSet.
• contains() method is a non-static method, it is accessible with the class object only, and if we try to access the method with the class name then we will get an error.
• contains() method does not throw an exception at the time of testing the existence of the given object.

Syntax:

    public boolean contains (Object ob);

Parameter(s):

• Object ob – represents the object whose existence is to be checked.

Return value:

The return type of the method is boolean, it returns true when the given object exists otherwise it returns false.

Example:

// Java program to demonstrate the example 
// of boolean contains (Object ob) method of HashSet 

import java.util.*;

public class ContainsOfHashSet {
    public static void main(String[] args) {
        // Instantiates a HashSet object
        HashSet < String > hs = new HashSet < String > ();

        // By using add() method is to add
        // the given object of this
        // HashSet 
        hs.add("C");
        hs.add("C++");
        hs.add("JAVA");
        hs.add("PHP");
        hs.add("SFDC");

        // Display HashSet
        System.out.println("HashSet: " + hs);

        // By using contains() method is to 
        // check whether the given object exists
        // or not exists in this HashSet
        boolean status = hs.contains("JAVA");

        // Display Status
        System.out.println("hs.contains(JAVA): " + status);
    }
}

Output

HashSet: [JAVA, C++, C, SFDC, PHP]
hs.contains(JAVA): true