public class StandardSystemPropertyTest extends TestCase {

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

  public void testGetValue() {

        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);

        }

        public String fromPropertyNameToFieldName(String propertyName) {
            return propertyName;
        }

        public String fromFieldNameToPropertyName(String fieldName) {
            return fieldName;
        }

        public String fromPropertyNameToGetterName(String propertyName) {
            return "get" + capitalizeName(propertyName);
        }

        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));

         *
         * @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);
    }

    /**
     * Find field using cache for improved performance.
     */
    private Field findCachedField(Class<?> beanType, String fieldName) {
        Map<String, Field> classFieldCache = FIELD_CACHE.computeIfAbsent(beanType, this::buildFieldCache);
        return classFieldCache.get(fieldName);
    }

    /**
     * Build field cache for a class.
     */
    private Map<String, Field> buildFieldCache(Class<?> beanType) {

        }
    }

    /**
     * Get field values.
     * @param document Document
     * @param fieldName Field name
     * @return Field values
     */
    protected String[] getFieldValues(final Map<String, Object> document, final String fieldName) {
        final Object value = document.get(fieldName);
        if (value instanceof String) {
            return new String[] { value.toString() };
        }

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)

         * @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);
    }