@Override
  public boolean hasData() throws ReplicationException {
    try {
      return conn.getAdmin().tableExists(tableName);
    } catch (IOException e) {
      throw new ReplicationException("failed to get replication queue table", e);
    }
  }
HBase table based replication queue storage.
hbase-replication/src/main/java/org/apache/hadoop/hbase/replication/TableReplicationQueueStorage.java