J2ME - Read and write to the record store

From: http://www.java2s.com/Code/Java/J2ME/Readandwritetotherecordstore.htm

/*--------------------------------------------------
* ReadWrite.java
*
* Read and write to the record store.
*
* No GUI interface, all output is to the console
*
* Example from the book:     Core J2ME Technology
* Copyright John W. Muchow   http://www.CoreJ2ME.com
* You may use/modify for any non-commercial purpose
*-------------------------------------------------*/
import javax.microedition.rms.*;

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.io.*;

public class ReadWrite extends MIDlet
{
  private RecordStore rs = null;
  static final String REC_STORE = "db_1";

  public ReadWrite()
  {
    openRecStore();   // Create the record store
   
    // Write a few records and read them back
    writeRecord("J2ME and MIDP");
    writeRecord("Wireless Technology");   
    readRecords();
   
    closeRecStore();  // Close record store
    deleteRecStore(); // Remove the record store
  }

  public void destroyApp( boolean unconditional )
  {
  }

  public void startApp()
  {
    // There is no user interface, go ahead and shutdown
    destroyApp(false);
    notifyDestroyed();
  }

  public void pauseApp()
  {
  }

  public void openRecStore()
  {
    try
    {
      // The second parameter indicates that the record store
      // should be created if it does not exist
      rs = RecordStore.openRecordStore(REC_STORE, true );
    }
    catch (Exception e)
    {
      db(e.toString());
    }
  }   
 
  public void closeRecStore()
  {
    try
    {
      rs.closeRecordStore();
    }
    catch (Exception e)
    {
      db(e.toString());
    }
  }

  public void deleteRecStore()
  {
    if (RecordStore.listRecordStores() != null)
    {
      try
      {
        RecordStore.deleteRecordStore(REC_STORE);
      }
      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;

      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);
        System.out.println("Record #" + i + ": " + new String(recData, 0, len));
        System.out.println("------------------------------");                       
      }
    }
    catch (Exception e)
    {
      db(e.toString());
    }
  }

  /*--------------------------------------------------
  * Simple message to console for debug/errors
  * When used with Exceptions we should handle the
  * error in a more appropriate manner.
  *-------------------------------------------------*/
  private void db(String str)
  {
    System.err.println("Msg: " + str);
  }
}