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Thread: waitForCardPresent() within thread freezes applet under Ubuntu

  1. #1
    Join Date
    Apr 2010

    Question waitForCardPresent() within thread freezes applet under Ubuntu


    I am currently having some issues with the waitForCardPresent() function in a Java applet.

    I am developping an applet that manages PC/SC communications.
    In my applet I need to check card Status.
    To do I use a Thread , I have created a CardStatus class that manages the work of the thread (this class extends Thread).

    Here is how I start my thread :
    cs = new CardStatus();
    cardStatusThread = new Thread(cs);

    I use EventListeners to notify my applet once waitForCardPresent() has finished.

    The run() of my thread consists of (I have simplified the code) :
                if(Reader != null)
                    try {
                        if(!Reader.isCardPresent()) // the reader is set by the applet  using a SetReader() function defined in CardStatus class
                                        this.NotifyPresentListeners(); // this  function notifies the applet that a card has been found
                    } catch (CardException e) {
                        // TODO Auto-generated catch block
    This applet is signed.
    I successfully manage to run this applet using windows, but I can't when using Ubuntu : the applet freezes until I put a card in the reader.

    I have tried to replace the Reader.waitForCardPresent(0); instruction with Thread.sleep(50000); to check if there was a mistake from the way I was using my thread, in that case my applet doesn't freeze under Ubuntu ; so I am guessing that it is the waitForCardPresent function that causes the trouble.

    I know that it could not be a security issue, because I have created an un signed applet that uses WaitForCardPresent (not within a thread, within the main code of the applet, just to test this) and I had no problem with it.

  2. #2
    Join Date
    Apr 2010

    Re: waitForCardPresent() within thread freezes applet under Ubuntu

    I re arranged a bit my code and put more displays to get a better idea of what's going on.

    I now know what is causing this : the waitForCardPresent method throws the following Exception : javax.smartcardio.CardException: wait mismatch
    at resent(

    I have searched a bit around for this exception and found this :

    Apparently this exception is thrown when a card isn't present and the timeout as expired, but I set the timeout to 0 (TIMEOUT INFINITE). Replacing 0 with TIMEOUT_INFINITE (0xffffffff) doesn't work.

    Any idea why do get this exception?

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