code: private void updateChromosomeChunks(String chromosome, int numChunks, Connection conn) throws SQLException {
          // insert all the chunks for that chromosome
          String minorChunkSuffix = (chunkSize / 1000) * 64 + "k";
  
          String sql = "insert into chunk (chunk_id, chromosome, start, end) values (?, ?, ?, ?)";
          PreparedStatement insertChunk = conn.prepareStatement(sql);
          conn.setAutoCommit(false);
          for (int i = 0, j = 1; i < numChunks; i++, j += chunkSize64k) {
              String chunkId = chromosome + "_" + i + "_" + minorChunkSuffix;
  //
  //            // check if this chunk is in the dabasete
  //            sql = "SELECT id FROM chunk where chunk_id = '" + chunkId + "'";
  //            ResultSet rs = stmt.executeQuery(sql);
  //            if (!rs.next()) {
              // if this chunk is not in the database, then insert it
              insertChunk.setString(1, chunkId);
              insertChunk.setString(2, chromosome);
              insertChunk.setInt(3, j);
              insertChunk.setInt(4, j + chunkSize64k - 1);
              insertChunk.addBatch();
  //            }
          }
          insertChunk.executeBatch();
          conn.commit();
          conn.setAutoCommit(true);
  
          initChunkMap();
      }
docs: Insert all the chunks for the given chromosome and update the internal map of chunks, if necessary.
  
  @param chromosome    Chromosome target
  @param numChunks     Number of chunks for that chromosome
  @param conn          Database connection
  Database connection