*
     * @param fieldName the name of the field to get configuration for
     * @return an OptionalThing containing the Config if the field exists and has a non-blank value,
     *         otherwise an empty OptionalThing
     */
    public OptionalThing<Config> getConfig(final String fieldName) {
        final String value = params.get(fieldName);
        if (StringUtil.isNotBlank(value)) {

     * Searches the class hierarchy to find the field.
     */
    private Object getField(Object obj, String fieldName) throws Exception {
        Class<?> clazz = obj.getClass();
        while (clazz != null) {
            try {
                java.lang.reflect.Field field = clazz.getDeclaredField(fieldName);
                field.setAccessible(true);
                return field.get(obj);

    // Helper methods

    private Object getFieldValue(Object obj, String fieldName) {
        try {
            Field field = getField(obj.getClass(), fieldName);
            field.setAccessible(true);
            return field.get(obj);
        } catch (Exception e) {
            throw new RuntimeException("Failed to get field value: " + fieldName, e);
        }
    }

public class StandardSystemPropertyTest extends TestCase {

  public void testGetKeyMatchesString() {
    for (StandardSystemProperty property : StandardSystemProperty.values()) {
      String fieldName = property.name();
      String expected = Ascii.toLowerCase(fieldName).replaceAll("_", ".");
      assertEquals(expected, property.key());
    }
  }

  public void testGetValue() {

     * Returns whether the {@link FieldDesc} exists.
     *
     * @param fieldName
     *            The field name. Must not be {@literal null} or empty string
     * @return Whether the {@link FieldDesc} exists
     */
    boolean hasFieldDesc(String fieldName);

    /**
     * Returns the {@link FieldDesc}.
     *
     * @param fieldName
     *            The field name. Must not be {@literal null} or empty string

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)

        Field field = findField(target.getClass(), fieldName);
        field.setAccessible(true);
        field.set(target, value);
    }

    private Field findField(Class<?> clazz, String fieldName) {
        while (clazz != null) {
            try {
                return clazz.getDeclaredField(fieldName);

         *
         * @param source The source value
         * @param fieldName A description of the field being interpolated. The implementation may use this to
         *         log stuff.
         * @return The interpolated value.
         */
        String transform(String source, String fieldName);
    }

         * @param source The source value
         * @param fieldName A description of the field being interpolated. The implementation may use this to
         *                           log stuff.
         * @return The interpolated value.
         */
        String transform(String source, String fieldName);
    }

        while (jsonParser.nextToken() != JsonToken.END_OBJECT) {
            final String fieldName = jsonParser.getCurrentName();
            if (fieldName != null) {
                jsonParser.nextToken(); // Move to the value of the current field

                if (jsonParser.getCurrentToken() == JsonToken.START_ARRAY) {
                    nestedMap.put(fieldName, parseArray(jsonParser));