Java Online Compiler

Write, compile, and run Java code online for free. Use custom standard input and view program output without installing OpenJDK.

Run the program
Output
Run Java Code Online
This free Java online compiler runs a single source file named Main.java in an isolated execution environment. Edit the starter program, provide optional input, and select Run to see standard output and compiler errors.
How to Use the Java Compiler
  1. Write or paste a complete Java program in the code editor.
  2. Add input in the Input tab when the program reads from standard input.
  3. Select Run. Compilation errors, runtime errors, and program output appear in the Output panel.
Java Execution Notes
Keep the public class named Main so it matches Main.java. The compiler builds the class before running its main method.
Programs can read values using Scanner, BufferedReader, or System.in. Execution time, memory, processes, output size, and network access are limited to keep the shared compiler responsive and secure.
Frequently Asked Questions
Do I need to install Java?
No. Compilation and execution happen remotely, so the editor works from a modern browser on desktop or mobile.
Can I provide input to my program?
Yes. Enter one or more lines in the Input tab before selecting Run. The text is passed to the program through standard input.
Continue learning with the Java tutorials and examples.