Capitalize the Starting Letter of Each Word in a Sentence Example...

Introduction

Capitalize the starting letter of each word in a sentence is a classic Java console program that demonstrates the concept with complete source code and sample output. Strings are immutable objects in Java; the examples show comparison, searching and transformation.

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

A string can be converted to uppercase using .toUpperCase() method.

Example Program

import java.util.Scanner;

class CapitalizeFirstLetter {

    public static void main(String[] args) {
        System.out.println("Enter the sentence to capitalize the first letter : ");
        Scanner scanner = new Scanner(System.in);
        String string = scanner.nextLine();
        Scanner stringScanner = new Scanner(string);
        String resultString = "";
        while (stringScanner.hasNext()) {
            String str = stringScanner.next();
            resultString = resultString + str.substring(0, 1).toUpperCase() + str.substring(1) + " ";
        }
        System.out.println("After capitalizing the first letter in each word, result is : " + resultString);
    }
}

Sample Output

Enter the sentence to capitalize the first letter :
java is an object-oriented programming language
After capitalizing the first letter in each word, result is: Java Is An Object-Oriented Programming Language

When to use

Use string manipulation when cleaning user input, parsing text files or formatting messages.

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

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

5. String string = scanner.nextLine(); updates a variable used in the calculation or output.

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

7. String resultString = ""; updates a variable used in the calculation or output.

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

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.