Online Java Compiler

Write, run, and share code snippets — no setup required.

Main.java

Alice
30

Output

Click Run to see the output here.

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String name = in.nextLine();
        int age = Integer.parseInt(in.nextLine());
        System.out.printf("Hello, %s! You are %d years old.%n", name, age);
    }
}

Run Java online in your browser

A free online Java playground and compiler. Write Java in your browser, hit Run, and the code compiles and executes on JDK 24 (Eclipse Temurin) in seconds. No local JDK, no Maven, no Gradle to set up first.

The editor is built on the same engine as VS Code, so Java syntax highlighting, autocompletion, and error squiggles all work. Code compiles on JDK 24 with Gson pre-installed for JSON — useful for exploring streams, records, pattern matching, or prepping for a Java interview without scaffolding a Maven or Gradle project.

What makes this Java playground useful

Instant Java execution — write code, press Run, and see output from the online Java compiler (JDK 24) in seconds.
Full Java syntax highlighting, autocompletion, and clear compile errors, powered by the same editor engine as VS Code.
Stdin input is wired into Scanner(System.in), BufferedReader(new InputStreamReader(System.in)), and System.in.read(). They all read from the playground's input box. No JDK, Maven, or Gradle to configure on your end.
JDK 24 (Eclipse Temurin) with Gson pre-installed — parse and serialize JSON out of the box, plus streams, records, and pattern matching.

What you can build in the Java playground

Streams, Optional, records, and pattern matching: modern JDK 24 idioms you can try one method at a time.
Data structure exercises, short algorithm problems, or a quick Gson JSON serialize/deserialize snippet.
Interview-style problems that read input with Scanner. Feed stdin lines from the input box and solve array, string, or tree problems end-to-end.

Online Java playground FAQ

Is the online Java playground free?

Yes, the Java playground is free to use. No sign-up, no install, and no JDK to configure — open the page and compile.

Do I need the JDK installed to use the online Java compiler?

No install needed. You don't need the JDK, Maven, or Gradle on your machine. The online Java compiler runs your code on JDK 24 (Eclipse Temurin) and returns the output in seconds.

Does the Java playground work on mobile and Chromebooks?

Yes. The Java playground runs in any modern browser, on desktop, tablet or mobile. It's a good option for running Java online from a Chromebook, iPad, or school computer where you can't install the JDK.

Does the Java playground support Scanner and System.in?

Yes. Scanner sc = new Scanner(System.in); sc.nextInt(); and BufferedReader-based patterns both read your typed lines exactly the way they would when you run java Main locally and type at the terminal. Good for interview-style problems.

How do I learn Java after trying the playground?

Edit the sample Java code, press Run, and iterate. When you want something more structured, Coddy's interactive Java course covers objects, inheritance, streams, and more with hands-on exercises.