Vijay Ramalingam

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since Jun 02, 2006
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Recent posts by Vijay Ramalingam

Hi
i tried startiung tomcat server, but the server not coming up due to the below error in catalina.out

java.lang.IllegalStateException: ContainerBase.addChild: start: LifecycleException: Failed to construct required crypto wrappers
Underlying exception: No current key found in publicKeyFile: /home/....../tomcat/conf/keys/public.key
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:764)


Could someone help on this issue ?

Thanks
-vijay
12 years ago
hi selvi..congrats great score.
15 years ago
Hi Narayana,
I did not take any mock exams at all. My first exam is the actual test itself.
15 years ago
Hi All ...i would like to start preparing for SCDJWS exam. I do not have a real-time experience in webservices.(i am aware of basic concepts of java webservice)
Please guide me where to start with and suggest me all the resources that i should use.


Thanks
-Vijay (SCJP1.4, SCWCD1.4, SCBCD5.0).
15 years ago
I used the book "Java EE 5 Development Using Glassfish Application Server" by David Heffelfinger for hands-on.
It teaches you to develop a sample EJB component, build , deploy and run. i used NetBeans6.1 integrated with glassfish server. You can try out all the sample example in this book which ever applicable to EJB3.0(skip servlet,JSF etc).
15 years ago
Hi All

Today I have passed SCBCD for Java EE 5.0 with a score of 93%. Though i am not a very active memeber of this forum, i find this forum discussion were quite useful.
I would like share some of my personal experience in passing the exam.

I started preparing for EJB 3.0 in May 2008. This time frame is too long.
Since i do not have any real-time project in EJB 2.1, i found it very hard to understand the
concepts of EJB 3.0. So, i started reading EJB 2.1 specfication in detail. Later i went for EJB 3 in Action following
EJB specifications core, persistence and simplified. It took me 3 months to understand and learn EJB3.0. From my personal
experience, EJB spec is the all-in-one that we have to read. It is just enough that you read the spec again and again and
and make sure you understood the concepts. No other material is needed. For last minute preparation, you will find very hard
in revising the spec, to overcome this start preparing the your own version of the spec,extracting the core concepts that
you have to memorize , while reading the sun spec(core, persistence and simpified).
Searching for mock exams , [ILLEGALLY COPIED MATERIAL] question paper is a mere waste of time and energy.
It is not just passing the exam, it is matter of fact how much we cover the topics.
We will never come again and read the topics in-depth, after passing the exam. This is one time chance, to gain knowledge.
Just concentrate on chapter 2-11 and chapter that explain migraation from EJB2.1 to EJB3.0 ijn EJB 3 in Action.
Mastering EJB 3.0 is a very good book, however it doesn't look good from exam point-of-view.
Make sure to have some hands-on before taking up the real exam.

If you have a real-time project experience, you would find easy passing the exam with a good score.

I hope the above is usefull.
15 years ago
Hi All

Today I have passed SCBCD for Java EE 5.0 with a score of 93%. Though i am not a very active memeber of this forum, i find this forum discussion were quite useful.
I would like share some of my personal experience in passing the exam.

I started preparing for EJB 3.0 in May 2008. This time frame is too long.
Since i do not have any real-time project in EJB 2.1, i found it very hard to understand the
concepts of EJB 3.0. So, i started reading EJB 2.1 specfication in detail. Later i went for EJB 3 in Action following
EJB specifications core, persistence and simplified. It took me 3 months to understand and learn EJB3.0. From my personal
experience, EJB spec is the all-in-one that we have to read. It is just enough that you read the spec again and again and
and make sure you understood the concepts. No other material is needed. For last minute preparation, you will find very hard
in revising the spec, to overcome this start preparing the your own version of the spec,extracting the core concepts that
you have to memorize , while reading the sun spec(core, persistence and simpified).
Searching for mock exams , dump question paper is a mere waste of time and energy.
It is not just passing the exam, it is matter of fact how much we cover the topics.
We will never come again and read the topics in-depth, after passing the exam. This is one time chance, to gain knowledge.
Just concentrate on chapter 2-11 and chapter that explain migraation from EJB2.1 to EJB3.0 ijn EJB 3 in Action.
Mastering EJB 3.0 is a very good book, however it doesn't look good from exam point-of-view.
Make sure to have some hands-on before taking up the real exam.

If you have a real-time project experience, you would find easy passing the exam with a good score.

I hope the above is usefull.
15 years ago
"why don't bean class implement component interface if it has to implement
the same methods? Java class allowed to implement more then one
interface?"

In EJB 2.1 if the bean class directly implements the component interface, it allows the developer to write a code in the bean class, such that the refrence "this" could be accidently passed to another EJB. Since all EJB business method should be invoked via the EJBObject that the container provides/generates, this contract is advised by the EJB spec.
However not implementing the component interface by the bean prevents us to do compile time checks.
Example

public class ComponentInterfaceA extends Remote{
public void getA();
}

public class BeanImplA implements SessionBean, ComponentInterfaceA {

public void getA(){
//get another ejb reference say ComponentInterfaceB

ComponentInterfaceB.getB(this)// this is not allowed and should not be done

}

}

Hope i understood your question and answered.
i guess the reason would be to call PreDestroy method on the bean instance or on the call back handler....so it needs to activate the bean instance.
Thanks Gaurav,

But my question is invoking methods on Timer API and not calling getTimerService().

For example we could get the javax.ejb.Timer object from the serialized TimerHandle, and then invoke methods on it. As per the spec, the javax.ejb.Timer method invocation is allowed from businessmethod, afterCompletion and beforeCompletion.
My question is why it is restricted in other methods of stateful session bean.
Thanks Gaurav,

But my question is invoking methods on Timer API and not calling getTimerService().

For example we could get the javax.ejb.Timer object from the serialized TimerHandle, and then invoke methods on it. As per the spec, the javax.ejb.Timer method invocation is allowed from businessmethod, afterCompletion and beforeCompletion.
My question is why it is restricted in other methods of stateful session bean.