public static String getPublicHostname() {
    String publicHostname = System.getenv("PUBLIC_HOSTNAME");
    if (publicHostname == null) {
      publicHostname = System.getProperty("PUBLIC_HOSTNAME");
    }
    return publicHostname;
  }
@return returns the value of PUBLIC_HOSTNAME from either environment variable or system properties
llap-common/src/java/org/apache/hadoop/hive/llap/LlapUtil.java