如何使用“过程”方法将“安装”方法参数发送到读卡器？

Question

I wrote an applet for my java card and I want to send the arguments of install method to the CAD. so I defined two static variables named theArray and arrayLength in my applet. And after that I made a copy of the install method arguments inside the body of that method. Finally I tried to return this variables to CAD in the process method. But in the response of SELECT command, the card returns SW=6F00 .

package bArrayAccessibilty;

import javacard.framework.APDU;
import javacard.framework.Applet;
import javacard.framework.ISOException;
import javacard.framework.Util;

public class BArrayReturner extends Applet {

    public static byte[] theArray;
    public static short arrayLength;

    private BArrayReturner() {
    }

    public static void install(byte bArray[], short bOffset, byte bLength)
            throws ISOException {

        new BArrayReturner().register();
        BArrayReturner.arrayLength=(short)bArray.length;
        Util.arrayCopyNonAtomic(bArray, (short)0,BArrayReturner.theArray , (short) 0, BArrayReturner.arrayLength);    


    }

    public void process(APDU apdu) throws ISOException {
        byte[] buffer=apdu.getBuffer();
        Util.arrayCopyNonAtomic(BArrayReturner.theArray, (short)0,buffer , (short) 0, BArrayReturner.arrayLength); 
        apdu.setOutgoingAndSend((short)0, (short)255);
    }

Note that, Initialization of the static fields, doesn't change anything.
I mean, I tried this lines in the class body also :

public static byte[] theArray=null;
public static short arrayLength=0;

But nothing changed.

What is wrong in my program?

Answer 1

The install method gets called when you install te applet.
The process method gets called when you (select first and)send a command to an instantiated/installed applet.
This means that the install method will get called first and thus:
your first error is tat you want to write to an uninitialized array(theArray == null)
your second error is the wrong parameters for Util.arrayCopyNonAtomic(take care for the offsetParameter handed over by the install method)