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Java program to get the elements from the TreeSet collection that are less than the specified item

Given a TreeSet collection, we have to get the elements that are less than the specified item.
Submitted by Nidhi, on June 06, 2022

Problem statement

In this program, we will create a TreeSet collection with integer elements. Then we will get the elements from the TreeSet collection that are less than the specified item using the headSet() method.

Source Code

The source code to get the elements from the TreeSet collection that are less than a specified item is given below. The given program is compiled and executed successfully.

Example of TreeSet.headSet() Method in Java

// Java program to get the elements from the TreeSet collection 
// that are less than the specified item

import java.io.*;
import java.util.*;

public class Main {
  public static void main(String args[]) {
    TreeSet < Integer > tree = new TreeSet < Integer > ();

    tree.add(30);
    tree.add(20);
    tree.add(25);
    tree.add(10);

    TreeSet < Integer > headset = (TreeSet < Integer > ) tree.headSet(27);

    System.out.println("Headset is: " + headset);
  }
}

Output

Headset is: [10, 20, 25]

Explanation

In the above program, we imported the "java.util.*", "java.io.*" packages to use the TreeSet class. Here, we created a public class Main.

The Main class contains a main() method. The main() method is the entry point for the program. And, created a TreeSet collection tree and added integer elements using add() method. Then we get the elements from the TreeSet collection that are less than the specified item using the headSet() method and printed the result.

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