Please help me regarding ServiceDemo example application

Question

Hi Friends..
Currently i use Java Card 2.2.1, and i use JCDK 2.2.1..
There's a ServiceDemo example application that shipped with JCDK 2.2.1..
There are some files, as follows :
1. Main class that extends javacard.framework.Applet
2. TestService class that extends BasicService
3. PreProcess class
4. PostProcess class
The PreProcess class and PostProcess class contains nothing, there's only it's default constructor in it..
    private Dispatcher disp;
    private Service serv;
    public Main()
        disp = new Dispatcher( (short) 1);
        serv = new TestService();
        disp.addService(serv, Dispatcher.PROCESS_COMMAND);
        register();
    }In that code, it seems that the all processes handled by TestService class...
What is the advantages while we use "Service" based java card?.. Is it more good than RMI based Java Card?..
Do i've to send the APDU command while i want to do the specific process provided?..
Is this often used in the kind of Java Card Application?..
Thanks in advance..

Answer 1

Thanks Shane for your reply.. :)
If i rely on SecureRMIPurse directly without know the basic of Pre-process and Post-process, i think its difficult enough for me.. :(
Could you guide me the very simple Pre-process and Post-process?..
Assume that i describe this function in the PreProcess and PostProcess class :
public class PreProcess {
    public PreProcess() {
    public byte addOne(byte add){
         return ++add;
public class PostProcess {
    public PostProcess() {
    public byte subtractOne(byte subtract){
         return --subtract;
}And then how to call either PreProcess's addOne method or PostProcess's subtractOne method from TestService class?..
Is it only through new operator?..
PreProcess preproc=new PreProcess();
preproc.addOne(1);
PostProcess postproc=new PostProcess();
postproc.subtractOne(5);Is this way a good implementation?..
Please correct me if i'm wrong..
Thanks in advance..