public JsonObject getHostChangesJson(String hostChangesFile) {
    if (hostChangesJson == null) {
      hostChangesJson = readFileToJSON(hostChangesFile);
    }
    return hostChangesJson;
  }
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