Discussion Board

Results 1 to 2 of 2
  1. #1
    Registered User
    Join Date
    Aug 2007

    Error on opening MfStandardConnection


    i try to read and write to an external Mifare 1k card with the 6131nfc.
    Everytime i try to open an MFStandardConnection i get the error:
    "No Class Def Found ... Cannot create class in system package"

    This lines causing the error:

    public void targetDetected(TargetProperties [] tProp) {

    Class trial[] = tProp[0].getConnectionNames();
    { //this line causing the error
    MFStandardConnection conn = (MFStandardConnection)Connector.open(((tProp[0].getUrl(trial[1]))));

    catch (Exception e) {


    I read hear in the discussion board that this error is caused by an outdated firmware. So i updated my phone to version 5.11.
    But the error still occurs.
    In the emulator from sdk1.1 the code works and i'm able to read an external card via cardreader.

    So, what i'm doing wrong?

    Another question: is the mifare api really fully implemented in this firmware version.

    I hope someone can give me a hint how to solve this problem.

    I'm thankful for any help.


  2. #2
    Nokia Developer Expert
    Join Date
    Oct 2005

    Re: Error on opening MfStandardConnection

    Hi Markus,

    You get "No Class Def Found ... Cannot create class in system package" when you create classes to system packages (ie. java.io, javax.microedition...). You should check that you are not having any own class in those packages. Probably the class that produces that problem is told in the exception that you got?

    Also you used parameter tProp[0].getUrl(trial[1]) to open connection.
    You should check that MFStandardConnection exists in TargetProperties got when tag is read and that it is used as a parameter for getUrl method.
    Last edited by samuuh; 2007-08-21 at 14:02.

Similar Threads

  1. Read an external MiFare card - using MFStandardConnection
    By zinxed in forum Near Field Communication
    Replies: 0
    Last Post: 2007-08-10, 10:35
  2. Error Message opening
    By neababz in forum General Messaging
    Replies: 0
    Last Post: 2007-07-30, 12:28
  3. opening a socket connection
    By bhatti81 in forum Mobile Java Networking & Messaging & Security
    Replies: 4
    Last Post: 2003-07-16, 10:08
  4. nokia 7210 modem via IR doesn't work !
    By oussamaaiadi in forum PC Suite API and PC Connectivity SDK
    Replies: 1
    Last Post: 2003-03-06, 10:46
  5. Replies: 1
    Last Post: 2002-10-14, 02:47

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts