protected Path generateOutputDirectory() {
    final String outputDirectory =
      OUTPUT_DIRECTORY_PREFIX + "/" + table + "-" + System.currentTimeMillis();
    return new Path(outputDirectory);
  }
Returns Random output directory path where HFiles will be generated
hbase-mapreduce/src/test/java/org/apache/hadoop/hbase/util/bulkdatagenerator/BulkDataGeneratorTool.java