protected final Map<String, Object> getChildren() {
        HashMap<String, Object> ret = new LinkedHashMap<>();
        Field[] fields = getClass().getDeclaredFields();
        for (Field field : fields) {
            field.setAccessible(true);
            Object fieldValue;
            try {
                fieldValue = field.get(this);
            } catch (IllegalAccessException e) {
                throw new ConfigurationRuntimeException(e);
            }
            if (fieldValue instanceof Node
                    || fieldValue instanceof NodeVector<?>
                    || fieldValue instanceof Map<?,?>)
                ret.put(field.getName(), fieldValue);
        }
        return ret;
    }
Overrides {@link Node#postInitialize(String)}.
Perform post initialization on this node's children.

@param configId The config id of this instance.
config-lib/src/main/java/com/yahoo/config/InnerNode.java