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Online Java Compiler

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

Main.java
Output
Click Run to see the output here.

Run Java online in your browser

This is a free online Java playground and compiler. Write Java code directly in your browser, hit Run, and execute on JDK 24 (Eclipse Temurin) in seconds — no local JDK, no Maven, no Gradle required. It's the fastest way to try a new language feature, work through an interview problem, or debug a short snippet.

Under the hood, the editor uses the same engine as VS Code (Java syntax highlighting, autocompletion, error squiggles), and your code compiles on JDK 24 with Gson pre-installed for JSON. Whether you're exploring streams, records, pattern matching, or prepping for a Java interview, this online Java compiler goes from idea to output in seconds — no Maven or Gradle project to scaffold.

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 — the same editor engine that powers VS Code.
  • Stdin input supported — Scanner(System.in), BufferedReader(new InputStreamReader(System.in)), and System.in.read() all read from the playground's input box. No install — no JDK, Maven, or Gradle to configure.
  • JDK 24 (Eclipse Temurin) with Gson pre-installed — parse and serialize JSON out of the box, use 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 completely free — no sign-up, no install, 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 works on any modern browser — desktop, tablet, or mobile. Great 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. The playground has a stdin input box — 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. Great 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 structured practice, Coddy's interactive Java course covers objects, inheritance, streams, and more with hands-on exercises.