private void buildConfigJson(Multimap<AbstractUpgradeCatalog.ConfigUpdateType, Entry<String, String>> propertiesToLog,
                               JsonObject serviceJson, String configType) {
    JsonElement configJson = null;
    configJson = serviceJson.get(configType);
    JsonObject configJsonObject = null;
    if (configJson != null) {
      configJsonObject = configJson.getAsJsonObject();
    } else {
      configJsonObject = new JsonObject();
    }
    buildConfigUpdateTypes(propertiesToLog, configJsonObject);
    serviceJson.add(configType, configJsonObject);
  }
Find, read, and parse the log4j.properties file.
@return the properties that were found or empty if no file was found
ambari-server/src/main/java/org/apache/ambari/server/configuration/Configuration.java