Found this very useful when i was trying out the JNI under android (Short Story – Could not get it to work!). Step #1: Start with a simple java class package org.apache; public class HelloWorld { public static void main(String[] args) { System.out.println("Hello World!"); } } Compile the java class C:\android\CmdLine>javac -d . -g Helloworld.java Step #2: Package the generated classes into a tempo