Example: Remove Vowels using StringBuilder in Java

// Remove Vowels using StringBuilder
import java.util.Scanner;

// Main class containing the entry point of the program
public class Main {
    public static void main(String[] args) {
        // Step 1: Define the input string
        String originalString = "Java Development";
        System.out.println("Original String: " + originalString);

        // Step 2: Initialize a StringBuilder to efficiently build the new string
        StringBuilder sb = new StringBuilder();

        // Step 3: Define a string containing all vowels for quick lookup
        String vowels = "aeiouAEIOU";

        // Step 4: Iterate through each character of the original string
        for (int i = 0; i < originalString.length(); i++) {
            char ch = originalString.charAt(i);

            // Step 5: Check if the character is a vowel
            // If the character's index in the 'vowels' string is -1, it's not a vowel.
            if (vowels.indexOf(ch) == -1) {
                sb.append(ch); // Append non-vowel characters to StringBuilder
            }
        }

        // Step 6: Convert StringBuilder to String and print the result
        String stringWithoutVowels = sb.toString();
        System.out.println("String without Vowels: " + stringWithoutVowels);

        // Example with user input
        Scanner scanner = new Scanner(System.in);
        System.out.print("\nEnter another string: ");
        String userInput = scanner.nextLine();
        StringBuilder userSb = new StringBuilder();
        for (int i = 0; i < userInput.length(); i++) {
            char ch = userInput.charAt(i);
            if (vowels.indexOf(ch) == -1) {
                userSb.append(ch);
            }
        }
        System.out.println("Processed String: " + userSb.toString());
        scanner.close();
    }
}