How to Convert HashSet to ArrayList in Java

Example 1 : Convert HashSet to ArrayList Using Parameterized Constructor

In this example, We created HashSet and add elements using add() method . Now we will initialize ArrayList Using Parameterized Constructor with HashSet elements .

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;

public class HashSetToArraylist {
	
	public static void main(String[] args) {
		
		//create HashSet
		HashSet<String> hashSet = new HashSet<String>();
		
		//add element into HashSet using add() method
		hashSet.add("Java");
		hashSet.add("Vogue");
		hashSet.add("Welcomes");
		
		//print HashSet Element 
		System.out.println("HashSet Elements : "+ hashSet);
		
		
		// Converting HashSet to ArrayList
	    List<String> list = new ArrayList<String>(hashSet);

	    //print ArrayList elements
	    System.out.println("ArrayList Elements :"+list);
				
	}

}

Output:

HashSet Elements : [Java, Vogue, Welcomes]
ArrayList Elements :[Java, Vogue, Welcomes]

Example 2 : Convert HashSet to List Using addAll() Method

In this example we will convert hashset to arraylist using addAll() method of List . Firstly we created HashSet then add element into it using add() method . Then we will create list. Now we will add HashSet elements to list using List’s addAll() method .

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;

public class HashSetToArraylist1 {
	
	public static void main(String[] args) {
		
		        //create HashSet
				HashSet<String> hashSet = new HashSet<String>();
				
				//add element into HashSet using add() method
				hashSet.add("Java");
				hashSet.add("Vogue");
				hashSet.add("Welcomes");
				
				//print HashSet Element 
				System.out.println("HashSet Elements : "+ hashSet);
				
				
				//create ArrayList
			    List<String> list = new ArrayList<String>();

			    //adding HashSet Element to Arraylist 
			    list.addAll(hashSet);
			    
			    //print ArrayList elements
			    System.out.println("ArrayList Elements :"+list);
			    
	}

}

Output:

HashSet Elements : [Java, Vogue, Welcomes]
ArrayList Elements :[Java, Vogue, Welcomes]

Example 3 : Convert HashSet to List Using add() Method

In this approach,we will convert HashSet to ArrayList using for loop . We created HashSet and add elements into it. We also created one list. Now We Iterate HashSet Using for-each loop and one by one element of HashSet will added to list using add() method . Let,s see java program for this approach .

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;

public class HashSetToArraylist2 {
	
	public static void main(String[] args) {
		
		//create HashSet
		HashSet<String> hashSet = new HashSet<String>();
		
		//add element into HashSet using add() method
		hashSet.add("Java");
		hashSet.add("Vogue");
		hashSet.add("Welcomes");
		
		//print HashSet Element 
		System.out.println("HashSet Elements : "+ hashSet);
		
		   
		//create ArrayList
	    List<String> list = new ArrayList<String>();

	    //add HashSet element to ArrayList one by one using loop 
	     for (String element : hashSet) {
	    	 
	    	 //add element in to list 
		     list.add(element);
	      }
	    
	    //print ArrayList elements
	    System.out.println("ArrayList Elements :"+list);
	}

}

Output:

HashSet Elements : [Java, Vogue, Welcomes]
ArrayList Elements :[Java, Vogue, Welcomes]

In this tutorial we have learned different method for HashSet to ArrayList conversion . You can learn more java HashSet Example for practice .

Read More:                                                                                                                       A Guide to HashSet
 A Guide To ArrayList
 Java Doc – HashSet