*       Stream.map}).
 *   <li><b>Do not</b> call {@link #doForward} or {@link #doBackward} directly; these exist only to
 *       be overridden.
 * </ul>
 *
 * <h3>Example</h3>
 *
 * <pre>
 *   return new Converter&lt;Integer, String&gt;() {
 *     protected String doForward(Integer i) {
 *       return Integer.toHexString(i);
 *     }
 *

  private static final class ShortConverter extends Converter<String, Short>
      implements Serializable {
    static final Converter<String, Short> INSTANCE = new ShortConverter();

    @Override
    protected Short doForward(String value) {
      return Short.decode(value);
    }

    @Override
    protected String doBackward(Short value) {
      return value.toString();
    }

    @Override

  private static final class ShortConverter extends Converter<String, Short>
      implements Serializable {
    static final Converter<String, Short> INSTANCE = new ShortConverter();

    @Override
    protected Short doForward(String value) {
      return Short.decode(value);
    }

    @Override
    protected String doBackward(Short value) {
      return value.toString();
    }

    @Override

  }

  private <F, T> Converter<F, T> defaultConverter(
      final TypeToken<F> convertFromType, final TypeToken<T> convertToType) {
    return new Converter<F, T>() {
      @Override
      protected T doForward(F a) {
        return doConvert(convertToType);
      }

      @Override
      protected F doBackward(T b) {
        return doConvert(convertFromType);
      }

  }

  private <F, T> Converter<F, T> defaultConverter(
      final TypeToken<F> convertFromType, final TypeToken<T> convertToType) {
    return new Converter<F, T>() {
      @Override
      protected T doForward(F a) {
        return doConvert(convertToType);
      }

      @Override
      protected F doBackward(T b) {
        return doConvert(convertFromType);
      }

      implements Serializable {
    static final Converter<String, Integer> INSTANCE = new IntConverter();

    @Override
    protected Integer doForward(String value) {
      return Integer.decode(value);
    }

    @Override
    protected String doBackward(Integer value) {
      return value.toString();
    }

    @Override

  private static final class FloatConverter extends Converter<String, Float>
      implements Serializable {
    static final Converter<String, Float> INSTANCE = new FloatConverter();

    @Override
    protected Float doForward(String value) {
      return Float.valueOf(value);
    }

    @Override
    protected String doBackward(Float value) {
      return value.toString();
    }

    @Override

      implements Serializable {
    static final Converter<String, Double> INSTANCE = new DoubleConverter();

    @Override
    protected Double doForward(String value) {
      return Double.valueOf(value);
    }

    @Override
    protected String doBackward(Double value) {
      return value.toString();
    }

    @Override

  private static final class FloatConverter extends Converter<String, Float>
      implements Serializable {
    static final Converter<String, Float> INSTANCE = new FloatConverter();

    @Override
    protected Float doForward(String value) {
      return Float.valueOf(value);
    }

    @Override
    protected String doBackward(Float value) {
      return value.toString();
    }

    @Override

      implements Serializable {
    static final Converter<String, Double> INSTANCE = new DoubleConverter();

    @Override
    protected Double doForward(String value) {
      return Double.valueOf(value);
    }

    @Override
    protected String doBackward(Double value) {
      return value.toString();
    }

    @Override