arpita kale

My question is why static member variable is used in singleton pattern?
In my project there is one class called as IDMConfig.The code of it is as follows.

public class IDMConfig {

private static IDMConfig obj;

private IDMConfig() {
init();
}
private void init(){
System.out.println("init method");
}

public static IDMConfig getInstance() {
if (obj == null)
obj = new IDMConfig();
return obj;
}

}

Object of IDMConfig is called from various classes in application like the following
IDMConfig.getInstance();

but init method which is called inside constructor..This method is only calling at the first time.If we logout the application and login then also this method is not calling?? and if we do the restart of websphere then only this method is calling next time.Can anybody explain me why this might be happening?
why member variable here is declared as static ?what is the use of this?

is session expiry is required to check in webapplication?In my project it is not checked at all.what will happen we do not add this check ?
I have seen most of the project code where this is checked at each request.
How to add session expiry check ?

My project is based on java,jsp,servlet.
I am working on enhancemenmt of this project.
In this project,in any action class of jsp,session expiry check is not present.Everwhere just session is taken without cheking wheather it is expired or not.Is such check is reaaly required?I saw this type of session expiry check in most of the webapplication projects.If we do not apply it then what will happen at the session expiry?
And also how to check session is expired or not in java?

Ok Thanks .I will try by this way.

I wnat to add three tabs on jsp page using html tags.
On click of tab I want to show some textboxes on jso then on click of next tab click another content should display and so on...
But I do not know how to add tabs in jsp using html tag.If anybody is knowing ,could you please help me regarding the same?

Hi

Congrats!!Great score!!!
have you worked on EJB? I am preparing for the exam.Head first EJB and specifications ,is this two only sufficient?Exam covers more specification questions or more Head first EJB level questions?

We deploy ear file which contains jar and war�

So when we deploy ear then both client part and bean part will be on the same machine��then application will not de deployed on two or more jvms.

Most of the time ear file is used for deployment then mostly client part and ejb part both will be deployed on one server one jvm.

but ejb is mostly used for distributed applications.
if we deploy only bean code on one jvm and other part(client code ) on other machine �.then here we will use ear file or not ?

How we will deploy code in two jvms?how we are deploying it on two machines ?

Please clear this concept.I want to run call session bean example method from one jvm to other jvm client code.I want guidelines to do it??

Hello Everybody
I have one conceptual question here.I want to know how ejb is related to distributed technology.I read from internet.I got the following points from internet.
After client server model,there are some disadvantages for client-server model.Therefore multitier application also called as distributed applications required to developed.In a multi-tier application, only the user interface stays on local machines while the logic of the application runs in the middle tier on a server. The final tier is still the stored data. When the logic of an application needs updating, changes are made to the software of the middle tier on the server, greatly simplifying the management of updates.But creating reliable, secure, and easily managed distributed applications is notoriously difficult. For example, managing transactions over a distributed system is a major task. Fortunately, using components that follow the EJB specification to build distributed systems relieves much of the burden.

If I develop webapplication...then jsp of applicataion is presentation part....classes will contain business logic part and database will reside on some anoather machine...So my war file will contain all .class files and jap files.I will deploy the war file on server say websphere.Then here the application becomes 3 tier.I can access the application from machine if I provide url and portno of that application.Then here where the concept of EJB requires.EJB uses RMI mechanism ...here where the remote method invocation requires...In which case differents jvms will be required?and Rmi and Ejbs will be required???I want an example about it.?what do you mean by component model ?

I am preparing for scbcd.But before starting i am not getting the purpose of EJB itself.Everywhere it is explained in verymuch technical terms.I am not able to get it properly.CAN ANYBODY CLERIFY THIS TO ME ?

Thank you very much for the reply.One more question is If I gave scbcd 1.3 then is it useful for me in future?or is it like that it is totally out dated so giving this exam is just waste of time.
Because if documents for scbcd 1.5 are less then I will prefer to go for scbcd 1.3.I have only 2 months remaining for exam praparation.so better to go for scbcd 1.3.But please clerify my above doubt that how it is useful to give this exam in future ?

I gave scjp 1.4 .Then is it possible for me to give EJB 3.0 exam scbcd 1.5?
Or is it like that I gave scjp 1.4 so I have to give scbcd 1.3 EJB 2.0? If anybody is having any idea about it, please let me know?

Hello everybody
I am new to this forum.First time I am posting a question in it.
I completed scjp 1.4 and scwcd 1.4 exam.Now I want to give exam scbcd.I searched on net,It is showing versions of scbcd as scbcd 1.3 and scbcd 1.5.
Which version exam I can give ?scbcd 1.3/Scbcd 1.5?what about scbcd 1.4?This version is not exist or what?which is the latest version?Head first EJB book I bought it.Is it for scbcd 1.3 or scbcd 1.5?
scbcd 1.3 covers EJB 2.0 or EJB 3.o?for which exam I can appear after giving scjp1.4?

I have lot of confusion before starting preparation.I have only 2 months remaining for exam.Please let me know the above details.