Set up your computer

Run Java on your own computer

• This playground is great for learning — but it runs on our server.
• For your own projects, it helps to set Java up on your computer.
• It takes about 15 minutes, and you only do it once.

Step 1 — Install the JDK

• To run Java you need a JDK (Java Development Kit) on your computer.
• A free, easy choice is Eclipse Temurin from adoptium.net — pick JDK 21.
• Download the installer for your system (Windows, macOS, or Linux) and run it.

Step 2 — Install VS Code

• VS Code (Visual Studio Code) is a free, popular code editor from Microsoft.
• Get it from code.visualstudio.com and install it.
• This is where you will write and run your code.

Step 3 — Add the Java extension

• Open VS Code and click the Extensions icon on the left.
• Search for Extension Pack for Java (the one by Microsoft) and click Install.
• It adds run buttons, colours, and helpful hints for Java.

Step 4 — Check it worked

• Open a terminal (in VS Code: Terminal → New Terminal) and type:

java --version

• You should see something like openjdk 21. If you do, you are ready.

Step 5 — Run your first file

• In VS Code, make a new file called Main.java and type:

public class Main {
    public static void main(String[] args) {
        System.out.println("Hello from my own computer!");
    }
}

• Press the ▶ Run button (top right) above the main method.
• You just ran Java outside the browser.