How to Reverse a String in Java

Today, I'm going to show you how to reverse a string in Java. Reversing a string means changing the order of its characters, so "Hello" becomes "olleH". This is a common task in programming, and I’ll teach you how to do it using a simple Java program.

Let’s break it down into simple steps to understand how we can reverse a string in Java.

Step 1. Import Necessary Classes.

To get started, we need to import two important classes.

1. Scanner: This is used to get input from the user.
2. StringBuilder: This will help us efficiently reverse the string.

Step 2. Create the Main Class.

Next, we create a Java class and a main method. The main method is where the program starts.

Step 3. Get User Input.

We will ask the user to enter a string that they want to reverse. We will use the Scanner class to read the user’s input.

Step 4. Reverse the String.

To reverse the string, we will use a loop that goes through the string from the end to the beginning and adds each character to a StringBuilder object.

Step 5. Display the Reversed String.

Finally, we will display the reversed string.

Java Code to Reverse a String

Here’s the Java code that performs these steps.

import java.util.Scanner;  // Import Scanner class to get user input

public class Reversestring {  // Define the class name
    public static void main(String[] args) {  // The main method
        Scanner scanner = new Scanner(System.in);  // Create Scanner object for input
        System.out.println("Enter string which need to be reversed");  // Prompt user for input

        // Capture the string entered by the user
        String original = scanner.nextLine();  

        // Create a StringBuilder to store the reversed string
        StringBuilder reversed = new StringBuilder();

        // Loop through the original string from end to start
        for (int i = original.length() - 1; i >= 0; i--) {
            reversed.append(original.charAt(i));  // Append each character in reverse order
        }

        // Print the reversed string
        System.out.println("Reversed String: " + reversed.toString());  // Output the reversed string

        // Close the scanner to free up resources
        scanner.close();
    }
}

Output

Conclusion

Reversing a string in Java is an easy task that we can achieve using the StringBuilder class and a loop. Today, you learned how to.

• Accept input from the user using Scanner.
• Reverse the string by looping through it from the end to the beginning.
• Print the reversed string.

This method is efficient and works perfectly for all string reversal tasks. I hope you find this guide helpful, and if you have any questions, feel free to ask!