satishkumar janakiraman

I am a newbie in J2EE.

When i was going through the Entity listeners, the declaration looks like

@Entity @EntityListeners({EmployeeDebugListener.class}) public class Employee { .... }

Instead i expect the otherway round, it should be like

@EntityListeners @ListenerEntities({Employee.class}) //a new annotation public class EmployeeDebugListener { .... }
I feel the second approach is extendable, say for example, if i want to write a new listener for the existing entities, it would be easy to do it in the second approach. All i have to do is that write a new listener class and associate all the entities that the new listener is willing to handle.

Can someone explain why it is done in the other way?

Hi,

I am trying to inspect the value of my ValueObject and this exception occurs only in debug mode. You are exactly correct, this exception
may occur in toString method.

any idea>?

sat

Hi,

Any information on this issue? I would like to hear some solution.

sat

Hi Roel,

No stack trace. This is happening only in debug mode. Thats why I am not able to provide more information.

sat

Hi,

This question may seem to be not related to SCJD but I found this exception while testing my SCJD assignment. When retrieving my data from the database file, I am getting this exception in my TransferObject
com.sun.jdi.InvocationException occurred invoking method..

Please let me know any of you getting similar exception.


sat

Hi Roberto,

Thanks for your reminder. Its working as expected in both modes.
sat

Hi,


I am not sure about the format but I am sure that XML style tags should not be used and also your file name must be suncertify.properties.

sat

Hi,

I have used conventional Synchronization technique for my locking in my assignment. I used Roberto's tool for verifying my locking and it is running normally but with RecordNotFoundException . I think this behaviour is normal and expected

Does it mean my locking strategy work fine? My requirement says

Any attempt to lock a resource that is already locked should cause the current thread to give up the CPU, consuming no CPU cycles until the desired resource becomes available.

To meet this requirement, I use wait() in lock method and also use notifyAll in unlock method. Does it sound good ? or Am I doing something different? Is there any solution to verify the above requirement?

PS: Thanks to Roberto's for his tool. It's

sat

Hi Roel,

I have used the traditional client identification technique using the combination of System time in milliseconds and random number. I just wanted to know other efficient techniques than this. I thought that MAC Address will be more efficient

sat

Hi,

Change the following line this.add(jspMain); . Add your splittpane into the contentPane of the frame.
this.getContentPane().add(jspMain);

sat

Hello Andrew,

If you send only the MAC address, you could not differentiate the two clients who were started in the same machine. But we can easily differentiate the clients by attaching some unique number (probably a system time in milliseconds) with the MAC Address before sending.
What do you think about this solution?

sat

Hi Roberto,

I have a cookie requirement. I have implemented my cookie generation in the server using the technique current time & random number . I will send this cookie to the client and use before adding, updating, deleting the records.

I just wanted to know other different approaches for the client identification rather than using current time & random number. I thought using MAC address instead of the conventional way (random number & current time). Attach some unique key with the MAC Address of the server and then send to the client and then use that value for subsequent client calls


sat

Hi,

I have a question about identifying the client. Is there any good solution for identifying the client in unique way? I came across some solutions which were employed the following techniques

Thread ID

New Data Instance

Milliseconds and Random number combination

etc.

I just thought MAC Address will be helpful for identifying the client in unique way. I would like to know the consequences of this strategy. Please post your comments & views on this.


sat

Hi Folks

I've observing.....and my assignment have 3 GUI's very similar - local client, remote client and server starter . I mean....all of then have one central panel with input datas and one south painel with 2 buttons...local client and remote client have "connect" and "exit" buttons....server stater have "start" and "exit" buttons.
Wich is the best approach to solve this implementation ?
1. Duplicate all code inside all classes ?
2. Use an inteligent config painel with MVC like Dennis's DVD that in runtime display apropriated widgets ?
3. Use inheritance, centralizing the duplicate code in some super-class ?
4. There are anothers approach ?
What do you ranches have used or thought about ?
Regards.

Hi,

I think it is also a design decision. I have used separate class for each mode. For example, local mode UI consists of view, model and controller. Similarly 3 classes for network client and server. In this design, code might be duplicated across other classes but it seems to be an elegant design. If there is a modification in any one of the modes, the modification will not impact other modes. It will eliminate the possibility of producing new bugs during maintenance



I am also eagerly waiting for some others response

sat

Hi,

I have also not implemented the Observer pattern. In my application user must click the retrieve button to get the latest data after updating or deleting the record.


sat