Thursday, April 9, 2009

Our first official book review in on its way...

by Eduardo Rodrigues

Great news!

We have been contacted (surprisingly) by Packt Publishing a few days ago and asked if we would be interested in read one of their new books and then publish an independent review here in the blog. We were very honored and flattered with the offer, so we obviously accepted it.

The book is "Processing XML documents with Oracle JDeveloper 11g" by Deepak Vohra.

One good thing that immediately caught my attention as soon as the book arrived today was seeing the name "Frank Nimphius" in the list of reviewers. This is certainly a good sign :)

Anyway, Fabio and I already have the book and we'll both read it and then compile our comments in a 4-hand post to come. We hope it wont take too long (and also hope this will be just the first of many other book reviews to come).

Cheers and keep reading!

Tuesday, March 24, 2009

Java and the Timezones

by Fábio Souza

Timezone, when using Java, can be something tricky. You can get surprised when you change your OS timezone (something common to countries with DST) and it doesn't take any effect on your Java programs. What does Sun have to say about that? It can be found at their FAQ:

Do my operating system's timezone patches fix the Java platform's timezone data?

No. The Java SE platform's timezone data is not read from the local or host operating system. The Java SE platform maintains a private repository of timezone data in locally installed files (.../jre/lib/zi) as part of the Java Runtime Environment (JRE) software. Applying whatever operating system timezone patches (for example Solaris OS, Linux, Windows) will have no effect on the accuracy of the Java SE platform's timezone data.

Sun recommends you to maintain all JVM up to date to avoid Timezone problems. To specific cases where a Timezone update is needed, they provide a tool called TZUpdater. TZUpdater is a JAR that contains timezone informations provided by Olson Timezone Database. To update the JVM's timezone you need to execute TZUpdater's most recent version like this:

java -jar tzupdater.jar -u (don't forget to check if you have read/write access to Java's directory structure)

We are ok about Sun's JVM... But the solution is the same to all JVMs? Not really =), but it is very similar to IBM JVM and Oracle JRockit. In all cases we either have to download a program and execute it to update the installed JVM or wait for the next JVM update release.

Here are some useful links:


IBM (thanks to my friend and co-worker Frederico Hakamine):


Tuesday, February 10, 2009

Web Component Developer Exam (SCWCD) for JEE 5

by Wellington Carvalho

I hope my feedback can help those who want to prepare for The Web Component Developer exam (SCWCD) for JEE 5. I will use the same structure of an older post that Fabio Souza wrote to pass his own experience with SCJP 5 exams.

Main reading resource

Head First Servlets and JSP: Passing the Sun Certified Web Component Developer Exam

The first edition of the book deals with J2EE 1.4 spec, but the changes in JEE 5 were
most related to EJB 3, so I think you won’t have troubles with the exam! But if you want, the second edition of the Head First Servlets and JSP is prepared for JEE 5 and you can find it here:

Main resources for exercises

I used an application similar to Whizlabz named Enthuware. Enthuware is an exercise tool with many tests that covers all the objectives mentioned by Sun. The exercises of Enthuware are very similar to the exam, and you have good explanations, no matter the answer is right or wrong.

In order to get a better performance in your study you should take the standard tests of Enthuware sequentially and exclusively when you have read the entire SCWCD book.
To evaluate your chapter’s knowledgement you should take the objective-wise tests only after reading the chapter. To get the full version of Enthuware you will spend around US$29,00 which is cheaper than the other: Whizlabz (US$74,95). If you fail the SCWCD exam the company guarantee your money back (must get at least 70% in the tests).

My study schedule

It took me 35 days to read all the 14 chapters and to do all the tests
and exercises of Enthuware. I spent 2 hours and a half per day to read the chapter and 1 hour to do the exercises. In the week before the exam I just took the standard tests and reviewed the material.

I think this schedule is reasonable to people that is working with JEE, however if you aren’t using JEE in your daily work you should reserve a longer study time.

The exam

In my opinion the exam is relatively easy to people that have work experience in JEE development, however you need to pay attention to every detail because the exam has good tricks hidden in the code. But don’t get scared. Most of them are covered by Enthuware.

To take this exam you must know about all the objectives listed by Sun, but with a special care on these below:

Servlet Technology Model
Expression Language (EL)
Custom Tag Library - Classic Model
JSP Standard Actions

It is important to remember that you need at least 70% to pass, but trust me (and Enthuware), if you start scoring more than 70% in the standard tests, you will pass easily.