Java HashSet contains() Method

The contains() method of Java HashSet class is used to check if this HashSet contains the specified element or not. It returns true if element is found otherwise, returns false.

Syntax

Following is the declaration of contains() method:

Parameter

Parameter	Description	Required/Optional
o	It is the element whose presence in this set is to be tested.	Required

Returns

The contains() method returns true if this set contains the specified element.

Exceptions

Compatibility Version

Java 1.2 and above

Example 1

import java.util.*;  
public class HashSetContainsExample1 {  
	public static void main(String[] args) {  
	    //Create hash set
	    HashSet<Integer> hset = new HashSet<Integer>();      
	    //Add elements to hash set
	    hset.add(11); 
	    hset.add(21);
	    hset.add(15);  
	    hset.add(110); 
	    hset.add(151); 
	    //Print HashSet elements
	    System.out.println("Hash set Elements: "+ hset);
	    //Check for "110" in the set
	  System.out.println("Does the Set contains '110'? :- "+hset.contains(110));	
	  //Check if the Set contains "555"
	  System.out.println("Does the Set contains '555'? :- "+hset.contains(555));
	  }  
}  

Output:

Hash set Elements: [21, 151, 11, 110, 15]
Does the Set contains '110'? :- true
Does the Set contains '555'? :- false

Example 2

import java.util.*;  
public class HashSetContainsExample2 {  
	public static void main(String[] args) {  
		//Get HashMap object from method init()
		@SuppressWarnings("rawtypes")
		HashSet studentSet = init();		
		//Ask input from console
		System.out.print("Enter student name:");
		Scanner s = new Scanner(System.in);
		String name = s.nextLine();
		s.close();				
		//Check if the console input is in the student database	
		if(studentSet.contains(name)){
			System.out.println(name +" found on student list.");
		}		
		else{
			System.out.println(name +" name not on the student list.");
		}
}
@SuppressWarnings("rawtypes")
private static HashSet init() {
	//CreateHashSet object
	HashSet<String> studentSet = new HashSet<>();
	//Add values to HashMap
	studentSet.add("Rishi");
	studentSet.add("Sharon");
	studentSet.add("Pawan");
	return studentSet;
	}  
} 

Output:

Enter student name: Rishi
Rishi found on student list.

Example 3

import java.util.*;
public class HashSetContainsExample3 {
	public static void main(String[] args) {
		//Create HashSet object
		HashSet<String> hashset = new HashSet<String>();				
		//Adding elements to HashSet
		hashset.add("Facebook");
		hashset.add("Twitter");
		hashset.add("Instagram");	
		//Print the elements of the HashSet
		System.out.println("Elements of the HashSet:");
		for(String val : hashset)
		{
			System.out.println(val);
		}
		//Check if the hashSet contains "Whatsapp"
		System.out.println("Does the HashSet contains 'Whatsapp'? :- "+hashset.contains("Whatsapp"));	
		//Check if the hashSet contains "Facebook"
		System.out.println("Does the HashSet contains 'Facebook'? :- "+hashset.contains("Facebook"));
	}
}

Output:

Elements of the HashSet:
Twitter
Instagram
Facebook
Does the HashSet contains 'Whatsapp'? :- false
Does the HashSet contains 'Facebook'? :- true

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Java HashSet contains() Method

Syntax

Parameter

Returns

Exceptions

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Example 1

Example 2

Example 3

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Java HashSet contains() Method

Syntax

Parameter

Returns

Exceptions

Compatibility Version

Example 1

Example 2

Example 3

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Preparation

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