code: public static Class<? extends VehicleInterface> findClass(
              String interfaceName) throws VehicleInterfaceException {
          Class<? extends VehicleInterface> interfaceType;
          try {
              interfaceType = Class.forName(interfaceName).asSubclass(
                      VehicleInterface.class);
          } catch(ClassNotFoundException e) {
              throw new VehicleInterfaceException(
                      "Couldn't find vehicle interface type " + interfaceName, e);
          }
          return interfaceType;
      }
docs: Obtain the Class object for a given VehicleInterface class name.
  
  The class must be in the classpath of the process' context, or an
  exception will be thrown.
  
  @param interfaceName the canonical name of class implementing
  {@link VehicleInterface}
  @return the Class object, if found.
  @throws VehicleInterfaceException if the named class could not be found
  or loaded.