HelloWorldApplet.java

package net.moznion.javacard.helloworld;

import javacard.framework.*;
import javacardx.framework.*;

public class HelloWorldApplet extends Applet {
    private final static byte HELLO_WORLD_CLA = (byte)0xB0;
    private final static byte SELECT_INS = (byte)0xA4;
    private final static byte HELLO_INS = (byte)0x50;
    private final static byte[] HELLO_TEXT = {(byte)'H',(byte)'e',(byte)'l',(byte)'l',(byte)'o'};

    private HelloWorldApplet() {
        register();
    }

    public static void install(byte[] bArray, short bOffset, byte bLength) {
        new HelloWorldApplet();
    }

    public boolean select() {
        return true;
    }

    public void deselect() {
    }

    public void process(APDU apdu) {
        byte[] buff = apdu.getBuffer();

        // ignore SELECT instruction
        if (buff[ISO7816.OFFSET_CLA] == 0 && buff[ISO7816.OFFSET_INS] == SELECT_INS) {
            return;
        }

        // check CLA
        if (buff[ISO7816.OFFSET_CLA] != HELLO_WORLD_CLA) {
            ISOException.throwIt(ISO7816.SW_CLA_NOT_SUPPORTED);
        }

        switch (buff[ISO7816.OFFSET_INS]) {
            case HELLO_INS:
                // do something
                short le = apdu.setOutgoing();
                if (le < (short)5) {
                    ISOException.throwIt(ISO7816.SW_WRONG_LENGTH);
                }
                apdu.setOutgoingLength((short)5);
                buff[0] = HELLO_TEXT[0];
                buff[1] = HELLO_TEXT[1];
                buff[2] = HELLO_TEXT[2];
                buff[3] = HELLO_TEXT[3];
                buff[4] = HELLO_TEXT[4];
                apdu.sendBytes((short)0, (short)5);
                return;
            default:
                ISOException.throwIt(ISO7816.SW_INS_NOT_SUPPORTED);
        }
    }

    public Shareable getShareableInterfaceObject(AID clientAID, byte parameter){
        return (Shareable)this;
    }
}