Java Program to Remove All Whitespaces from a String

1. Introduction

Removing all whitespaces from a string is a common requirement in text processing tasks. It involves eliminating spaces, tabs, and new line characters. This operation is useful in data normalization, input validation, and various other scenarios where whitespace is irrelevant or potentially problematic. In this blog post, we'll demonstrate how to remove all whitespaces from a string in Java.

2. Program Steps

1. Define the input string with whitespaces.

2. Use the replaceAll method of the String class to remove all whitespaces.

3. Display the original and the processed strings.

3. Code Program

public class RemoveWhitespaces {
    public static void main(String[] args) {
        // Defining the input string with whitespaces
        String inputString = "Java is fun to learn";

        // Using replaceAll method with regex to remove whitespaces
        String stringWithoutWhitespaces = inputString.replaceAll("\\s+", "");

        // Displaying the original and processed strings
        System.out.println("Original String: " + inputString);
        System.out.println("String without Whitespaces: " + stringWithoutWhitespaces);
    }
}

Output:

Original String: Java is fun to learn
String without Whitespaces: Javaisfuntolearn

Explanation:

1. The program begins by defining a string variable named inputString that contains whitespaces.

2. To remove the whitespaces, it uses the replaceAll method of the String class. The replaceAll method takes a regular expression as its first argument and a replacement string as its second argument. The regular expression \\s+ matches one or more whitespace characters (spaces, tabs, new line characters), and the replacement string is an empty string (""), effectively removing all matched whitespaces.

3. The processed string, now devoid of any whitespaces, is stored in a new variable named stringWithoutWhitespaces.

4. Finally, the program prints both the original string and the processed string to the console, allowing the user to see the effect of the whitespace removal operation.