public static String humanReadableTimestamp(final long timestamp) {
    if (timestamp == HConstants.LATEST_TIMESTAMP) {
      return "LATEST_TIMESTAMP";
    }
    if (timestamp == PrivateConstants.OLDEST_TIMESTAMP) {
      return "OLDEST_TIMESTAMP";
    }
    return String.valueOf(timestamp);
  }
Use for logging.
@param b Key portion of a KeyValue.
@param o Offset to start of key
@param l Length of key.
@return Key as a String.
hbase-common/src/main/java/org/apache/hadoop/hbase/KeyValue.java