Introduction:

Welcome to Session 2! In this session, we will guide you through creating your very first Java program using Eclipse. We’ll also break down the basic structure of a Java program so you can understand how everything fits together.

Step 1: Setting Up Eclipse

Before we dive into the code, ensure you have Eclipse IDE installed on your computer. If not, download and install it from here.

Step 2: Create a New Java Project

• Open Eclipse.
• Go to File > New > Java Project.
• Name your project: FirstJavaProgram.
• Click Finish. You now have a new Java project set up!

Step 3: Create a Java Class

• Right-click on the src folder in your project.
• Go to New > Class.
• Name your class: HelloWorld.
• Check the box for public static void main(String[] args).
• Click Finish.

You’ve now created a Java class with the main method, where your code will be executed.

Step 4: Write Your First Java Program

Replace the default code with the following:

 
      public class HelloWorld {
    public static void main(String[] args) {
        // This line prints "Hello, World!" to the console
        System.out.println("Hello, World!");
    }
}
     (code-box)

Step 5: Run the Program

• Click the Run button (the green play button) at the top of the Eclipse window.
• Check the Console: You should see the text Hello, World! printed.

Congratulations! You’ve just run your first Java program in Eclipse.

Explaining the Program Structure

Let’s break down the code:

• public class HelloWorld: This declares a class named HelloWorld. Every Java program must have at least one class.
• public static void main(String[] args): This is the main method where your program starts running. Without this, your program won’t execute.
• System.out.println("Hello, World!");: This line prints the text "Hello, World!" to the console. The System.out.println method is used to display output.

Key Points to Remember

• Java programs start executing from the main method.
• Classes and methods must be enclosed in curly braces { }.
• Every statement in Java ends with a semicolon ;.

Conclusion

Now you know how to create, run, and understand the basic structure of a Java program using Eclipse. Keep experimenting with different print statements and see what you can create!

Call to Action

Try modifying the System.out.println line to print your name or a different message. What happens when you remove the semicolon at the end of a statement? Experiment and learn!