How do I use ProGuard?

Question

I was trying to learn how to use ProGuard, and it is no way as easy as I thought. At first I found a simple Java code to try it, a simple two class Swing calculator.

Answer 1

I got it to work using the following configuration file:

-injars       calc.jar
-outjars      calc_obf.jar
-libraryjars  /lib/rt.jar
-keep class Calc {
  public static void main(java.lang.String[]);
}

Most notably, I ditched the public in front of class Calc.