How to "serialize to" and "retrieve from" objects from hsqldb

Assuming ChartData implements the serializable interface:

     String insertGraph ="INSERT INTO GRAFICI_BLOB (ID, DATA) VALUES (##, ?)"

    ChartData chartData = chartsPage.getChartData();
     // Serialize to a byte array
     ByteArrayOutputStream bos = new ByteArrayOutputStream();
     try {
         ObjectOutputStream out = new ObjectOutputStream(bos);
         out.writeObject(chartData);
         out.close();
     } catch (IOException e2) {
         e2.printStackTrace();
     }
     byte[] chartDataBytes = bos.toByteArray();

     PreparedStatement str1 = null;
     try {
         str1 = con.prepareStatement(insertGraph);
         str1.setBytes(1, chartDataBytes);
         str1.executeUpdate();
     } catch (Exception ex) {
         ex.printStackTrace();
     } finally {
         try {
             if (null != str1)
                 str1.close();
         } catch (Exception ex) {
         }

     }

/*
* and the way back
*/
          Statement stmt = con.createStatement();
          String sql = the query to select your blob field... (in my case GRAFICO)

          ResultSet res = stmt.executeQuery(sql);
          byte[] bytes = res0.getBytes("GRAFICO");
              // Deserialize from byte array
              try {
                  ObjectInputStream in = new ObjectInputStream(new ByteArrayInputStream(bytes));
                  runProperties.chartData = (ChartData) in.readObject();
                  in.close();
              } catch (IOException e) {
                  e.printStackTrace();
              } catch (ClassNotFoundException e) {
                  e.printStackTrace();
              }