First Java 8 Program

Overview

In this tutorial, we will create and run our first Java 8 program. We will write a simple "Hello, World!" application, compile it, and run it. This will help you get started with Java programming.

Step-by-Step Guide

1. Create a Java Source File

Create a new file with a .java extension. For this example, we will name it HelloWorld.java.

2. Write the Java Program

Open the HelloWorld.java file in a text editor or an Integrated Development Environment (IDE) and write the following code:

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

Understanding the Code

Let's break down the code:

• public class HelloWorld: This line declares a public class named HelloWorld. In Java, every application must have at least one class definition.
• public static void main(String[] args): This line declares the main method, which is the entry point of any Java application. The main method must be declared public, static, and must return void. It accepts a single parameter, an array of String objects.
• System.out.println("Hello, World!");: This line prints the string "Hello, World!" to the console. System.out is a standard output stream, and println is a method that prints a line of text to the console.

3. Compile the Java Program

Open a terminal or command prompt and navigate to the directory where you saved HelloWorld.java. Run the following command to compile the program:

javac HelloWorld.java

If there are no errors, this command will generate a file named HelloWorld.class in the same directory. This file contains the bytecode of the program, which can be executed by the Java Virtual Machine (JVM).

4. Run the Java Program

To run the compiled Java program, use the following command:

java HelloWorld

You should see the following output in the terminal or command prompt:

Hello, World!

Conclusion

Congratulations! You have successfully written, compiled, and executed your first Java 8 program. This is a fundamental step in learning Java programming, and you are now ready to explore more advanced concepts and features of Java 8.