Tomasz Czerwinski

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since Jun 04, 2012
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Recent posts by Tomasz Czerwinski

It`s a great book but it doesn`t cover all the details from the exam (even it`s authors wrote about it on some page).
Here you will find some very usefull info:
https://coderanch.com/t/573852/java-Web-Component-SCWCD/certification/Passed-OCEJWCD

You are right, it`s pretty confusing.

The case is that (as you wrote), when Servlet doesn`t implement SingleThreadModel, only one instance of it will be created. And if you synchronize one of it`s methods (service(..), doPost(..), etc), container won`t be abe to use full potential of concurrent executions. Request to this servlets will be serialized, because each request-thread will block servlet for the time of it`s execution.
This situation is even worse than implementing SingleThreadModel. When your servlet implement it, you mark it for the container and the container can create many instances of the Servlet and pool them, so each thread will work on different servlet instance and it won`t be blocked (of course if there will be enough servlet instances).

So, by 'cannot use the instance pool approach', I would understand that:
-container won`t be able to gain benefits from concurrent threads working on one servlet instance.
I forgot to write about tests I did before going on exam. I divided whole process into 2 steps for better knowledge consolidation:
1) I red 'HF JSP and Servlets 2nd edition'
1.1)All tests from Enthuware exam pack for SCWCD 5
1.2)Mock test from the book
2) I red Servlet 3.0 specification
2.1)All tests from Enthuware exam pack for OCPJWCD 6

I know that a lot of questions in Enthuware test packs were the same, but by doing this I felt VERY comfortable when I started to read specification and I knew all details mentioned there.
11 years ago
Hi all!

Last friday I managed to succeed in passing OCEJWCD 6 exam with 96%.

For all of you learning for this exam I recommend:
-HF: JSP and Servlets 2nd edition - although it doesn`t cover Servlets 3.0 specification.
-JSR-000315 - Java Servlet Specification 3.0 - it was my first specification to read directly and I was amazed how clearly is it written
-for asynchronous servlets, which are hard to understand without proper examples I reccomend reading:
--https://blogs.oracle.com/enterprisetechtips/entry/asynchronous_support_in_servlet_3
After it sit for an hour and write your own code. Async stops being 'magic' after writing and testing 2-3 example servlets.

It was very sad for me but you have to remeber servlet API. You HAVE TO remember methods and list of their arguments very well. I still dont get it why there are so many questions about such things - that you wont remember and won`t care one hour after going out of the exam center. But whatever you think about it be sure to be prepared for it.

If you have any questions feel free to ask me.

Best regards!
11 years ago