ERROR: java/lang/NoClassDefFoundError. HELP!!!

Question

Hi all, can any one tell me what's wrong with my program that runs fine in JavaONEStudio5, but i find following error message when i run it in WTK21:
Project "readWriteRights" loaded
Project settings saved
Building "readWriteRights"
Build complete
Running with storage root DefaultColorPhone
Uncaught exception java/lang/NoClassDefFoundError: ReadWriteRights.
Here is my simple program:
* readWriteRights.java
* A simple application program to read a text file
* and store it's content into a Record Store.
* the data is read from the Record Store for verification
* Created on 2004/4/8 2:29am
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.io.*;
import javax.microedition.rms.*;
import java.io.*;
public class readWriteRights extends MIDlet {
public readWriteRights() { } // constructor
public void startApp() throws MIDletStateChangeException {
     String fileName = "origin.drm";
     String field[] = new String [] {"","","","","","","",""};  // Total 8 constraints in the file
     int i = 0;
     // retrieve the contents of a resource file
     System.out.println("Retrieving the resource file - readme.txt");
     System.out.println("--------------------------------------------");
     InputStream is = this.getClass().getResourceAsStream(fileName);
     try {
          if ( is != null ) {
               int ch = is.read();
               while ( ch != -1) {
               // print out the contents of the readme file
               System.out.print((char) ch);
                    // temp = (temp-10)*2;   // decoding
                    if (ch == 10) { i++; } //skip it if the character is \n
                    else
                         field[i] += (char)ch;
                    if(i >= field.length)
                    { ch = -1;}
                    else{ ch = is.read();}
               is.close();
          } catch (IOException e) {
               System.out.println(e);
     // Write to a record store
     String rs_Name = "db1";
     RecordStore rs = null;
     try {
                 if ( exist(rs_Name) == true) {
          RecordStore.deleteRecordStore(rs_Name);
             }  // check and delete existing Record Store
          rs = RecordStore.openRecordStore(rs_Name,true);
          System.out.println("Record Store "+rs_Name+" is opened.");
     catch(Exception e){
          System.out.println("Error: "+e.getMessage());
     finally{
          //* write records
          for (int j = 0; j < field.length; j++)
               byte[] rec = field[j].getBytes();
               //close the record store
               try {
                    rs.addRecord(rec,0,rec.length);
                    System.out.println((j+1) +" record is added to db1");
                    System.out.println("Record: "+field[j]);
               catch (Exception e){System.out.println("Error: "+e.getMessage());}
          System.out.println("Write reord completed.");
          //* read records
          try {
               int len =50;
                        byte[] recData = new byte[len];
                        System.out.println("The data read from Record Store.");
               for (int k=1; k <= rs.getNumRecords(); k++)
                    len = rs.getRecord(k, recData, 0);
                    System.out.println("Record #"+k+": "+new String(recData, 0, len));
                    System.out.println("---------------------------------------------------");
          catch (Exception e){System.out.println("Error2: "+e.getMessage());     }
          // * close record Store
          try {
               rs.closeRecordStore();
               System.out.println("record store db1 is closed");
          catch (Exception e){System.out.println("Error: "+e.getMessage());}
destroyApp(true);
notifyDestroyed();
* The method to check if the Record Store existed or not
     public boolean exist(String recordStoreName) {
          boolean existF=true;
          RecordStore rs=null;
          if(recordStoreName.length()>32) return false;
               try {
                    rs=RecordStore.openRecordStore(recordStoreName,false);
               catch(RecordStoreNotFoundException e) {existF=false;}
               catch(Exception e){}
               finally{
                         try{
                              rs.closeRecordStore();
                         }catch(Exception e){}
          return existF;
} // end of check Record Store existance method          
* Pause the MIDlet
public void pauseApp() { }
* Called by the framework before the application is unloaded
public void destroyApp(boolean unconditional) { }
}

Answer 1

I doubt that the error is caused by " java.io.* " which is not included in MIDP so that my program cannot run in WTK21.. is that true?
if yes, what can I do with it because I have to run it in WTK21 for demonstration. thx!!!!!