package api;

 // BEGIN: theory.binary.constants.api

 public abstract class API {

     public static final int VERSION = 1;

     protected API() {

         System.err.println("Initializing version " + VERSION);

         init(API.VERSION);

         System.err.println("Properly initialized: " + this);

     }

     protected abstract void init(int version) throws IllegalStateException;

 }

 // END: theory.binary.constants.api