code: private void initHandlers() {
          registerHandler(Boolean.class,BooleanOptionHandler.class);
          registerHandler(boolean.class,BooleanOptionHandler.class);
          registerHandler(File.class,FileOptionHandler.class);
          registerHandler(URL.class, URLOptionHandler.class);
          registerHandler(URI.class, URIOptionHandler.class);
          registerHandler(Integer.class,IntOptionHandler.class);
          registerHandler(int.class,IntOptionHandler.class);
          registerHandler(Double.class, DoubleOptionHandler.class);
          registerHandler(double.class,DoubleOptionHandler.class);
          registerHandler(String.class,StringOptionHandler.class);
          registerHandler(Byte.class, ByteOptionHandler.class);
          registerHandler(byte.class, ByteOptionHandler.class);
          registerHandler(Character.class, CharOptionHandler.class);
          registerHandler(char.class, CharOptionHandler.class);
          registerHandler(Float.class, FloatOptionHandler.class);
          registerHandler(float.class, FloatOptionHandler.class);
          registerHandler(Long.class, LongOptionHandler.class);
          registerHandler(long.class, LongOptionHandler.class);
          registerHandler(Short.class, ShortOptionHandler.class);
          registerHandler(short.class, ShortOptionHandler.class);
          registerHandler(InetAddress.class, InetAddressOptionHandler.class);
          registerHandler(Pattern.class, PatternOptionHandler.class);
          // enum is a special case
          registerHandler(Map.class,MapOptionHandler.class);
  
          try {
              Class p = Class.forName("java.nio.file.Path");
              registerHandler(p, PathOptionHandler.class);
          } catch (ClassNotFoundException e) {
              // running in Java6 or earlier
          }
      }
docs: Registers the default handlers.