Java: Convert a hash set to a tree set

Last update on May 22 2025 13:14:30 (UTC/GMT +8 hours)

8. Convert HashSet to TreeSet

Write a Java program to convert a hash set to a tree set.

Sample Solution:

Java Code:

import java.util.*;
  public class Exercise8 {
  public static void main(String[] args) {
         // Create a empty hash set
     HashSet<String> h_set = new HashSet<String>();
   // use add() method to add values in the hash set
          h_set.add("Red");
          h_set.add("Green");
          h_set.add("Black");
          h_set.add("White");
          h_set.add("Pink");
          h_set.add("Yellow");
      System.out.println("Original Hash Set: " + h_set);
    
     // Creat a TreeSet of HashSet elements
     Set<String> tree_set = new TreeSet<String>(h_set);
 
     // Display TreeSet elements
     System.out.println("TreeSet elements: ");
     for(String element : tree_set){
        System.out.println(element);
     }
  }
}

Sample Output:

Original Hash Set: [Red, White, Pink, Yellow, Black, Green]            
TreeSet elements:                                                      
Black                                                                  
Green                                                                  
Pink                                                                   
Red                                                                    
White                                                                  
Yellow

Pictorial Presentation:

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Java program to convert a HashSet to a TreeSet and then print the elements in natural sorted order.
• Write a Java program to convert a HashSet to a TreeSet and verify that adding a new element maintains the sorted order.
• Write a Java program to compare the performance of converting a large HashSet to a TreeSet using different methods.
• Write a Java program to convert a HashSet to a TreeSet and then remove elements that do not meet a specified condition.

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