* @return コレクションの要素型
     */
    public static Class<?> getElementTypeOfCollection(final Field field) {
        assertArgumentNotNull("field", field);

        final Type type = field.getGenericType();
        return GenericsUtil.getRawClass(GenericsUtil.getElementTypeOfCollection(type));
    }

    /**
     * パラメタ化されたマップ型のフィールドのキー型を返します。
     *
     * @param field

        assertArgumentNotNull("field", field);
        assertArgumentNotNull("map", map);

        return createParameterizedClassDesc(field.getGenericType(), map);
    }

    /**
     * コンストラクタの引数型を表現する{@link ParameterizedClassDesc}を作成して返します。
     *
     * @param constructor
     *            コンストラクタ。{@literal null}であってはいけません
     * @param index

    }

    Field delegateField = SubBar.class.getDeclaredField("delegate");
    // barType is Bar<T>, a ParameterizedType with no generic arguments specified
    TypeToken<?> barType = TypeToken.of(delegateField.getGenericType());
    assertThat(barType.getSubtype(SubBar.class)).isEqualTo(new SubBar<Void>().fieldTypeAsSubBar());
  }

  @SuppressWarnings("unchecked") // To construct TypeToken<T> with TypeToken.of()

    }

    Field delegateField = SubBar.class.getDeclaredField("delegate");
    // barType is Bar<T>, a ParameterizedType with no generic arguments specified
    TypeToken<?> barType = TypeToken.of(delegateField.getGenericType());
    assertThat(barType.getSubtype(SubBar.class)).isEqualTo(new SubBar<Void>().fieldTypeAsSubBar());
  }

  @SuppressWarnings("unchecked") // To construct TypeToken<T> with TypeToken.of()

    public Inner field;

    class Inner {}
  }

  public void testInnerClassWithParameterizedOwner() throws Exception {
    Type fieldType = ParameterizedOuter.class.getField("field").getGenericType();
    assertEquals(
        fieldType, TypeToken.of(ParameterizedOuter.class).resolveType(fieldType).getType());
  }

  private interface StringIterable extends Iterable<String> {}

    public Inner field;

    class Inner {}
  }

  public void testInnerClassWithParameterizedOwner() throws Exception {
    Type fieldType = ParameterizedOuter.class.getField("field").getGenericType();
    assertEquals(
        fieldType, TypeToken.of(ParameterizedOuter.class).resolveType(fieldType).getType());
  }

  private interface StringIterable extends Iterable<String> {}

    for (Field field : fields) {
      if (Modifier.isPublic(field.getModifiers())
          && Modifier.isStatic(field.getModifiers())
          && Modifier.isFinal(field.getModifiers())) {
        if (field.getGenericType() == field.getType() && type.isAssignableFrom(field.getType())) {
          field.setAccessible(true);
          try {
            T constant = type.cast(field.get(null));
            if (constant != null) {

    for (Field field : fields) {
      if (Modifier.isPublic(field.getModifiers())
          && Modifier.isStatic(field.getModifiers())
          && Modifier.isFinal(field.getModifiers())) {
        if (field.getGenericType() == field.getType() && type.isAssignableFrom(field.getType())) {
          field.setAccessible(true);
          try {
            T constant = type.cast(field.get(null));
            if (constant != null) {

    } else {
      return null;
    }
  }

  /**
   * Returns the type token representing the generic type declaration of {@code cls}. For example:
   * {@code TypeToken.getGenericType(Iterable.class)} returns {@code Iterable<T>}.
   *
   * <p>If {@code cls} isn't parameterized and isn't a generic array, the type token of the class is
   * returned.
   */
  @VisibleForTesting