RivoCode

Java Fundamentals · Getting Started · Lesson 1 of 22

Your First Java Program

Concept

Your First Java Program

Every Java program lives inside a class, and execution begins in a special method called main. System.out.println prints a line of text to the console.

By the end of this lesson
  • Explain the core idea behind Your First Java Program.
  • Predict output before running a change.
  • Test one realistic and one unusual input.
  • Use the result to make the next decision.
How to study this page
  1. 1. Read one concept.
  2. 2. Change the example.
  3. 3. Run, compare, and explain.
  4. 4. Complete the challenge below.
ExampleRunnable
public class Main {
    public static void main(String[] args) {
        System.out.println("Hello, RivoCode!");
    }
}
Try it Yourself »
Self-check before continuing

Without looking at the example, describe what changes when you modify one input in Your First Java Program. Then reopen the editor and prove your explanation with a small test.

You are ready to continue when you can predict, test, and explain the result.

Your turn

Change the program to print your own name instead.

Loading editor…

Console

Output will appear here...