Sorted Set Interface Example in Java

Introduction

Sorted Set Interface is a classic Java console program that demonstrates the concept with complete source code and sample output. The Collections Framework provides ArrayList, HashMap, HashSet and related data structures.

This tutorial walks through the program line by line, explains how the logic works, and highlights best practices you can apply in your own code.

Definition

Unlike a regular set, the elements in a sorted set are sorted, either by the element’s compareTo() method, or a method provided to the constructor of the sorted set. The first and last elements of the sorted set can be retrieved, and subsets can be created via minimum and maximum values, as well as the beginning or ending at the beginning or end of the sorted set. The SortedSet interface is implemented by TreeSet.

Syntax

SortedSet<variable-type> variable-name= new TreeSet<variable-type>();

Sorted Set Interface Example Program

import java.util.Scanner;
import java.util.SortedSet;
import java.util.TreeSet;

public class SortedSetInterfaceExample {

    public static void main(String[] args) {
        SortedSet<String> sortedSet = new TreeSet<String>();
        System.out.println("Enter the input to be added in Sorted Set : ");

        Scanner scanner = new Scanner(System.in);
        String val1 = scanner.nextLine();
        String val2 = scanner.nextLine();
        String val3 = scanner.nextLine();
        String val4 = scanner.nextLine();

        sortedSet.add(val1);
        sortedSet.add(val2);
        sortedSet.add(val3);
        sortedSet.add(val4);

        System.out.println(sortedSet);
    }
}

Sample Output

Enter the input to be added in Sorted Set :
zoooooo
boooooo
noooooo
yoooooo
[boooooo, noooooo, yoooooo, zoooooo]

When to use

Use this sorted set interface example when learning or revising core Java syntax.

How it works

1. Execution begins in the main method — the JVM calls this method when you run the class.

2. import java.util.Scanner; imports a class used later in the program.

3. import java.util.SortedSet; imports a class used later in the program.

4. import java.util.TreeSet; imports a class used later in the program.

5. SortedSet<String> sortedSet = new TreeSet<String>(); updates a variable used in the calculation or output.

6. A println / print call writes text to the console — part of the sample output below.

7. A Scanner reads typed input from the keyboard (System.in).

8. A println / print call writes text to the console — part of the sample output below.

Best Practices

• Use meaningful variable and class names that describe their purpose.
• Compile and run the program locally — modify values to see how output changes.
• Read compiler errors carefully; they usually point to the exact line to fix.

Common Mistakes

• Copying code without understanding each line — practice by changing one statement at a time.
• Mismatching the public class name and the .java filename.
• Forgetting semicolons at the end of statements.