Java Program to Remove All Whitespace from a String

Introduction

Removing all whitespace from a string is a common task in text processing. This task helps you practice string manipulation in Java. This guide will walk you through writing a Java program that removes all spaces, tabs, and other whitespace characters from a given string.

Problem Statement

Create a Java program that:

• Prompts the user to enter a string.
• Removes all whitespace characters from the string.
• Displays the string without whitespace.

Example:

• Input: "Java programming is fun"
• Output: "Javaprogrammingisfun"

Solution Steps

1. Read the String: Use the Scanner class to take the string as input from the user.
2. Remove All Whitespace: Use the replaceAll() method to remove all whitespace characters.
3. Display the Result: Print the string without whitespace.

Java Program

// Java Program to Remove All Whitespace from a String
// Author: https://www.rameshfadatare.com/

import java.util.Scanner;

public class RemoveWhitespace {
    public static void main(String[] args) {
        // Step 1: Read the string from the user
        try (Scanner scanner = new Scanner(System.in)) {
            System.out.print("Enter a string: ");
            String input = scanner.nextLine();
            
            // Step 2: Remove all whitespace characters
            String noWhitespaceString = input.replaceAll("\\s", "");
            
            // Step 3: Display the result
            System.out.println("String without whitespace: " + noWhitespaceString);
        }
    }
}

Explanation

Step 1: Read the String

• The Scanner class is used to read a string input from the user. The nextLine() method captures the entire line as a string.

Step 2: Remove All Whitespace

• The replaceAll() method is used with the regular expression \\s to match all whitespace characters (spaces, tabs, newlines, etc.) and replace them with an empty string "".

Step 3: Display the Result

• The program prints the string without any whitespace using System.out.println().

Output Example

Example:

Enter a string: Java programming is fun
String without whitespace: Javaprogrammingisfun

Conclusion

This Java program demonstrates how to remove all whitespace from a user-input string. It covers essential concepts such as string manipulation, using regular expressions, and the replaceAll() method, making it a valuable exercise for beginners learning Java programming.