public static void main(String[] args) throws Exception {
    ToolRunner.run(HBaseConfiguration.create(), new MajorCompactorTTL(), args);
  }
This tool compacts a table's regions that are beyond it's TTL. It helps to save disk space and
regions become empty as a result of compaction.
hbase-server/src/main/java/org/apache/hadoop/hbase/util/compaction/MajorCompactorTTL.java