@SuppressWarnings("unchecked")
  @VisibleForTesting
  public static void expandConfigMap(
      Map<String, Object> config, String prefix, Map<String, Object> result) {
    for (Map.Entry<String, Object> entry : config.entrySet()) {
      String key = entry.getKey();
      Object value = entry.getValue();
      String fullKey = prefix.isEmpty() ? key : prefix + "." + key;
      if (value instanceof Map) {
        Map<String, Object> subMap = (Map<String, Object>) value;
        expandConfigMap(subMap, fullKey, result);
      } else {
        result.put(fullKey, value);
      }
    }
  }
Override the value of {@link SystemProperties}.
amoro-ams/src/main/java/org/apache/amoro/server/AmoroServiceContainer.java