Run Java 24 online

What's in Java 24

• JEP 485: stream gatherers ship stable — user-defined intermediate stream ops.
• JEP 484: class-file API is out of preview — replaces ASM for anyone parsing bytecode.
• JEP 491: synchronize virtual threads without pinning platform threads.

What you get in Java 24

Clicking "Run now" opens the playground with this exact code and a matching test case — passes on first Run.

import java.util.Scanner;
public class Solution {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    System.out.println(n * 2);
  }
}

How ls-judge runs Java 24

Every submission is compiled and executed inside its own Firecracker microVM — the same isolation primitive AWS Lambda uses. No shared container, no shared kernel with other users' code. The Java 24toolchain shipped with the microVM is the real thing (not a browser-side emulation): syscalls behave the way they do in production, and the compile / runtime behaviour matches what you would see on your own machine with that version installed.

Feed stdin from the Tests panel, watch verdicts stream per test case over a WebSocket. Free to use, no sign-up, works from any browser.