code: public static Class[] getClasses(String basePackage, Class requiredInterface)
      {
          return getClasses(basePackage, new Class[] {requiredInterface});
      }
docs: Returns an array of concrete classes in the given package that implement the
  specified interface.
  
  @param  basePackage the name of the package containing the classes to discover
  @param  requiredInterface the inteface that the returned classes must implement
  @return an array of concrete classes in the given package that implement the
  specified interface