internal fun <T> readFieldOrNull(
  instance: Any,
  fieldType: Class<T>,
  fieldName: String,
): T? {
  var c: Class<*> = instance.javaClass
  while (c != Any::class.java) {
    try {
      val field = c.getDeclaredField(fieldName)
      field.isAccessible = true
      val value = field.get(instance)
      return if (!fieldType.isInstance(value)) null else fieldType.cast(value)
    } catch (_: NoSuchFieldException) {
    }

     *             指定された名前のフィールドが見つからない場合
     * @see Class#getDeclaredField(String)
     */
    public static Field getDeclaredField(final Class<?> clazz, final String name) throws NoSuchFieldRuntimeException {
        assertArgumentNotNull("clazz", clazz);
        assertArgumentNotEmpty("name", name);

        try {
            return clazz.getDeclaredField(name);
        } catch (final NoSuchFieldException e) {

      Bar<T> delegate;

      TypeToken<SubBar<T>> fieldTypeAsSubBar() {
        return new TypeToken<SubBar<T>>() {};
      }
    }

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

      Bar<T> delegate;

      TypeToken<SubBar<T>> fieldTypeAsSubBar() {
        return new TypeToken<SubBar<T>>() {};
      }
    }

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

        def ultimateCause = new RuntimeException("ultimate cause")
        Field field = Throwable.class.getDeclaredField("cause")
        field.setAccessible(true)
        field.set(ultimateCause, ultimateCause)

        def branch1 = new DefaultMultiCauseException("first failure", ultimateCause)

            Field field = null;
            for (Class<?> clazz = mojo.getClass(); clazz != Object.class; clazz = clazz.getSuperclass()) {
                try {
                    field = clazz.getDeclaredField(resolution.getField());
                    break;
                } catch (NoSuchFieldException e) {
                    // continue
                }
            }
            if (field == null) {

    }

    private void setValueToObject(Object obj, String name, Object value) {
        Field field = ClassUtil.getDeclaredField(obj.getClass(), name);
        field.setAccessible(true);
        FieldUtil.set(field, obj, value);
    }

    public void test_pruneNode() throws Exception {

            InputSource v4src = loc != null ? loc.getSource() : null;
            if (v4src != null) {
                try {
                    Field field = InputSource.class.getDeclaredField("modelId");
                    field.setAccessible(true);
                    field.set(v4src, ModelProblemUtils.toId(model));
                } catch (Throwable t) {
                    // TODO: use a lazy source ?

                    org.apache.maven.api.model.InputSource v4src = loc != null ? loc.getSource() : null;
                    if (v4src != null) {
                        Field field = InputSource.class.getDeclaredField("modelId");
                        field.setAccessible(true);
                        field.set(v4src, ModelProblemUtils.toId(model));
                    }
                } catch (Throwable t) {

    }

    private final static ClassNode NO_CLASS;

    static {
        ClassNode cn = null;
        try {
            try {
                cn = (ClassNode) ClassNodeResolver.class.getDeclaredField("NO_CLASS").get(null);
            } catch (IllegalAccessException | NoSuchFieldException e) {
                cn = null;
            }
        } finally {
            NO_CLASS = cn;
        }
    }