Persistence of data in J2ME mobile device using RMS

Question

Hi. Just want to ensure that RMS can let us store some values in the mobile device. I'm using emulator to try this out. Everytime i close the emulator, the data stored in the RecordStore's gone. How about in real mobile device?
For some reasons, my jad and jar can't be installed in my Nokia 6210. It keeps giving me "Invalid Jar file" error.
So, my main question is whether RMS really stores the value in the mobile device and can be retrieved everytime that MIDlet app's run again.
The other question is why is it that my jar can't be installed in my Nokia 6210? I just built it with NetBean with J2ME and it could be run on the emulator perfectly.
Thanks a lot.

Answer 1

Hi. For the installation to my phone, i have solved it by changing my app's MIDP version 2.1 to 2.0.
For the persistence of data part, i changed the Storage->"Storage Root Directory" to "\save" in Preferences of SJWTK and re-run my app on the emulator and my phone. However, it seems that the record store's data is not persisted. So, i assume it has something to do with my code. My code is as below. Can anyone give me some clues on what i have done wrong? Thanks.
public TheConstructor(MIDlet midlet, Form form, int partnerId){
     try
      // The second parameter indicates that the record store
      // should be created if it does not exist
        rs = RecordStore.openRecordStore(REC_STORE_NAME, true );
        if (rs.getNumRecords() == 0) {
            RecordIdParam = getAdsParam();
            if (clientIdParam.length > 0) {
                clientId = RecordIdParam;
                writeRecord(RecordIdParam);
                readRecords();
                closeRecStore();  // Close record sto
        else {
            readRecords();
            closeRecStore();  // Close
     catch (Exception e)
      db(e.toString());
private void db(String str)
    System.err.println("Msg: " + str);
  public void closeRecStore()
    try
      rs.closeRecordStore();
    catch (Exception e)
      db(e.toString());
   public void writeRecord(String str)
    byte[] rec = str.getBytes();
    try
      rs.addRecord(rec, 0, rec.length);
    catch (Exception e)
      db(e.toString());
  public void readRecords()
    try
      // Intentionally make this too small to test code below
      byte[] recData = new byte[5];
      int len;
      System.out.println("num of records is " + rs.getNumRecords());
      for (int i = 1; i <= rs.getNumRecords(); i++)
        if (rs.getRecordSize(i) > recData.length)
          recData = new byte[rs.getRecordSize(i)];
        len = rs.getRecord(i, recData, 0);
        RecordIdParam = recData;
    catch (Exception e)
      db(e.toString());
  }