In this post, I will be sharing how to convert TreeSet to HashSet in Java. I have already shared the difference between HashSet and TreeSet in Java. There are 3 ways to achieve our goal of converting TreeSet to HashSet in Java.

1. Using HashSet constructor [Easiest]

2. Using for-each

3. Using addAll() method

Read Also : 3 ways to Convert HashSet to TreeSet in Java

Let's dive deep into the topic of converting TreeSet to HashSet in Java.

Convert TreeSet to HashSet in Java

1. Using HashSet constructor


The easiest way to convert TreeSet to HashSet in Java is by using HashSet constructor as shown below in the example:

 import java.util.*;

public class TreeSetToHashSet {
    public static void main(String args[]) {
      
      // Create a TreeSet object
      TreeSet<String> treeset = new TreeSet<String>();
      
      // Adding elements to TreeSet object
      treeset.add("India");
      treeset.add("USA");
      treeset.add("Canada");
      
      // Displaying TreeSet elements 
      System.out.println("Printing TreeSet elements: "+ treeset);
      
      // Converting TreeSet to HashSet using Constructor
      HashSet<String> hashset = new HashSet<>(treeset);
      
      // Printing HashSet elements
      System.out.println("Printing HashSet elements: "+ hashset);
    }
}


Output:
Printing TreeSet elements: [Canada, India, USA]
Printing HashSet elements: [Canada, USA, India]

2. Using for-each


Another way to convert TreeSet to HashSet in Java is by using for-each as shown below in the example:

 import java.util.*;

public class TreeSetToHashSet2 {
    public static void main(String args[]) {
      
      // Creating a TreeSet object
      TreeSet<String> treeset2 = new TreeSet<String>();
      
      // Add elements to TreeSet object
      treeset2.add("Element1");
      treeset2.add("Element2");
      treeset2.add("Element3");
      
      // Printing TreeSet elements 
      System.out.println("Displaying TreeSet elements: "+ treeset2);
      
      // Creating HashSet Object
      HashSet<String> hashset2 = new HashSet<>();
      
      // Converting TreeSet to HashSet using for-each
      for(String str : treeset2)
      {
          hashset2.add(str);
      }
      
      // Displaying HashSet elements
      System.out.println("Displaying HashSet elements: "+ hashset2);
      
    }
}


Output:
Displaying TreeSet elements: [Element1, Element2, Element3]
Displaying HashSet elements: [Element3, Element2, Element1]

3. Using addAll() method


We can also use addAll() method to convert TreeSet to HashSet in Java as shown below in the example:

 import java.util.*;

public class TreeSetToHashSet3 {
    public static void main(String args[]) {
      
      // Instantiating a TreeSet object
      TreeSet<String> treeset3 = new TreeSet<String>();
      
      // Putting elements to TreeSet object
      treeset3.add("Alive");
      treeset3.add("is");
      treeset3.add("Awesome");
      
      // Showing TreeSet elements 
      System.out.println("Showing TreeSet elements: "+ treeset3);
      
      // Instantiating HashSet Object
      HashSet<String> hashset3 = new HashSet<>();
      
      // Converting TreeSet to HashSet using addAll() method
      hashset3.addAll(treeset3);
      
      // Showing HashSet elements
      System.out.println("Showing HashSet elements: "+ hashset3);
      
    }
}


Output:
Showing TreeSet elements: [Alive, Awesome, is]
Showing HashSet elements: [Awesome, is, Alive]

That's all for today. Please mention in the comments if you have any questions related to how to convert TreeSet to HashSet in Java.