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Koji Muramoto

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Recent posts by Koji Muramoto

In EJB 2.x we could use the Service locator to cache Home interfaces (using jndi name as key). In EJB 3.0 one looks up directly to the business interface, that is you work directly with the proxy (no need to call home.create()) and caching can be a bad thing.

So the only real caching benefit of SL in EJB 3.0 is the caching of InitialContext, but for the exam though should I also consider caching of remote references as a benefit as well?
I tried to add handlers using @HandlerChain(file="handlerchain.xml"), but I got the following.



The service is a simple HelloWorld, RPC-style, no wsdl. Is there some extra configuration that needs to be done?


EDIT: DUH!

I have just copy/pasted the handlerchains.xml from SOA Using java webservices and they are missing the jws namespace. After fixing,

<jws:handler-chains xmlns:jws="http://java.sun.com/xml/ns/javaee">;
<jws:handler-chain>
<jws:handler>
<jws:handler-class>server.ServerMessageHandler</jws:handler-class>
</jws:handler>
</jws:handler-chain>
</jws:handler-chains>

it works.
[ December 10, 2008: Message edited by: Koji Muramoto ]
Yesterday I took the test and I did 65/69.

I used both HF 2nd editon and SCWCD exam study kit (Manning publishing), after studying HF for the first time. Both complement each other in my opinion. Manning's book is a bit more organized (and formal) and I liked better the sections on filters and tag files.

Well, I was disappointed in general with some of the questions, about 8 or so, where all about having that specific thing in your head, which by now I probably wouldn't know the answer. The test asking for intricacies of tags is OK in my opinion, since it's the kind of stuff which is very often put to use, but some things just the kind of stuff you'd be googling for the answer.

The most "real-life use" questions where about packaging rules and design patterns. I don't know if it was my impression, but I felt like there was a lot more scriplet code than EL and as usual there was the kind of stuff you'll never use.
11 years ago
Hello, I'm currently studying "SOA using java webservices", by Mark D. Hansen.

I like the book, but it's a shame I lack some formal knowledge on some subjects such as UDDI, XML schema, etc. The examples are nicely packaged for testing with ant/maven.

How helpful do you guys think this book is certification-wise? And which complementary reading should I be taking to prepare for the new SCDJWS?

Originally posted by Ismael Upright:
Hello,

In "EJB3 in Action" there is sample application named ActionBazaar. Here are my doubts:


1.
On the figure 2.2 (p.42) we can see that two operations "Billing" and "Order confirmation" are performed independently of each other and in parallel.

But on the other hand, in the begining of the chapter 2.2.2 there is a sentence: "One more process might be apparent: the backgroung billing process to charge the order, triggered by order confirmation". It looks for me that the "Order confirmation" is the predecessor operation to the "Billing" operation. So the figure 2.2 would look like that:

Place bid -> Bid end -> Order -> Order confirmation -> Billing -> Item shipped

What's up with that? Is it parallel or not?


2.
I'm not quite sure if this application is more like internet shop or rather internet auction?

- the story with Jenny and possible overbidding sounds like an auction

But:

- there is no overbidding mechanism like in the shop
- you have to confirm the order like in the shop (I always thought that on the auction simply bidding (or overbidding) is the confirmation as well and the person who won is obligated to pay... so there is no additional confirmation, just the info about winning the auction)


Thanks



It is paralel in the sense that calling the Bill Order is done via a Message Producer, thus it just delegates to a MDB to do some hypotetical intensive operation like sending an email/updating a DB, but sending the message to a queue is almost a non-blocking operation.

If you look further at page 58 you'll see that the PlaceOrderBean first saves the order then sends a message to bill it:

saveOrder(order); (blocking)
billOrder(order); (almost non-blocking)

Not trully paralell but the confirmOrder() method should return much faster than executing the billOrder logic in the same method.
I remind reading on HF EJB that one should wrap an unrecoverable/unexpected app exceptions such as SQLexceptions into EJBExceptions, however I haven't found anything regarding this issue on EJB 3.

I have 3 major doubts about this:

1)Is this still a recommendation? (well, what does the exam expect me to answer!)
2)Are there any other scenarios that one should rethrow an app exception wrapped into an EJBException to the client?
3)Can this cause poison messages? (Ex: if the Database is down a MDB will keep throwing EJBException and the message will never leave the queue)


Thanks in advance.