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Aitch Chung

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since Apr 26, 2010
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Recent posts by Aitch Chung

Why don't you use:

In this way, init() is called each time the component "shows" on the display list.
11 years ago
Hi, there.

I've recently developed a Flex project using WebService to communicate with Java EE. There're two services hosted on the server: UserService and TestService. When I try to use Factory pattern to create the web service instance as followed:

When I tried to load the wsdl of UserService and call the method as followed, everything was just fine:

But when I tried to do the following:

I got the fault message indicated that UserService's WSDL doese not contain any service titled as "testSomething". Of course, there is no any service titled as "testSomething", I changed the WSDL to another one, but the webServiceLocator instnace still searched the old wsdl AND the new WSDL. Is there anyone knows how to solve this problem, i.e., use the same web service instance to invoke the different methods from different service providers without using any framework (e.g. Cairngorm), but with the plain old school trick? Thanks
11 years ago

The bean managed transaction(a.k.a. BMT) let you do the transaction yourself, like, defining the demarcation of the transaction, when to commit and when to set rollback etc. The container managed tranaction let the container do the lifting.

Usual case of using persistence service provided by the container is let the container decide when to persist entities related. When the method returned, the tranaction ended also. Hence, the states of entities persisted to the db. In this case the beginning and end of the method defines the persistence scope. If you're using stateful session bean, client might go through many different methods which may need the data from method to method. Therefore, the demarcation limited to the method might not be applied. The extended scope for peresistence context can keep the entity manger from being destroied when the client goes through the methods, hence, for the following case:

Usual Persistence Context:

Exteneded Persistence Context:

I hope it helps.
Hi, everyone

I passed SCBCD yesterday. Since I learned from this forum, I think I should give feedback to this forum. I read the following materials for test:

1. SCBCD Study Guide 5.0, By Mikalai Zaikin
This study guide is great at providing objectives, but the content writing is not that good for digest.

2. EJB 3 in Action, By Debu Panda etc.
This book is so funny at explaining the Java EE technology, it's kind like Head First in EJB 3.0 with words, word, and words!

3. Enterprise JavaBeans 3.0, By Bill Burke etc.
I love this book's workbook part, it helps to completing the missing part of the previous one.

4. JSR 220: Enterprise JavaBeans[TM],Version 3.0 EJB Core Contracts and Requirements
This spec is so important to read, but hard to digest, finish it before you go to test.

You have to pay attention to the seven roles defined in the spec, especially the RESPONSIBILITIES of these roles at handling Exceptions, Security, and Basic Knowledge.

Pay special attention to JPQL aggregation functions, definitions etc.

Pay special attention to entity relationships at defining Cardinality, Generics, and Collection. e.g. How to define the many-to-many relationship for the following situation:

Assigning the correct relationship to the code provided above. The exam question is quite similar with the code above.

I've count the questions for passing the exam. There're 35 questions you can get the score easily, all you have to do is get 4 extra answers from guessing the answer, it's quite easy to derive the answer from the questions before/after the current question. Just be patient to go through all the questions TWICE, you can KNOW the answers from other questions!

I hope my experience helps.
11 years ago
Hi, everyone

I prepare the SCBCD exam for a while. I bought the uCertify mock exam few days ago. I'm wondering whether this mock exam helps or I should buy another mock exam instead? Thanks.