Skills101

Online Java compiler (Java 21)

Write code, add input, press Run. Free, no sign-up — your code stays in this browser.

Java editor

Output

Press Run to see your program’s output here.

Tips for Java

  • Your public class must be named Main.
  • Read input with Scanner (simple) or BufferedReader (fast).
  • Standard library only.
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Frequently asked questions

Is this online Java compiler free?
Yes. Compile and run Java 21 programs here for free without signing up.
Why must the class be called Main?
The runner compiles your file as Main.java and runs the Main class, so your public class must be named Main.
How do I read input in Java?
Type the input in the Input box and read it with Scanner sc = new Scanner(System.in); then sc.nextInt(), sc.next() or sc.nextLine().
Which Java version is used?
Java 21, so modern features such as records, var and switch expressions work.