How to Run .class Files on Android

What is a .class File?

A .class file is compiled Java bytecode created from a .java source file. With Jre4Android, you can run compatible CLASS files on Android.

Steps to Run a CLASS File

1. Open Jre4Android.
2. Select CLASS mode.
3. Choose your compiled .class file.
4. Enter or confirm the class name if required.
5. Run the class file and view output in the terminal.

Important Requirements

• The class should include a valid public static void main(String[] args) method.
• If the class uses a package name, the folder structure and class name must match.
• External dependencies may need to be included in the classpath.

Example

If your class is named Hello, it usually runs like this:

java Hello

If your class uses a package, such as com.example.Hello, you may need to run it with the full class name:

java com.example.Hello

Common Problems

Main method not found

Make sure the class contains a valid Java main method.

Class not found

Check the package name, folder structure, and classpath.

Java version mismatch

The CLASS file may have been compiled for a newer Java version than the runtime supports.