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Friday, 10 June 2011

Comments on EJB 3.0 Database Persistence with Oracle Fusion Middleware 11g, by Deepak Vohra

On the bright side, the text is well written,  providing a brief synopsis of the ejb 3, (not 3.01 which is the current) background and following a block by block explanation of each snippet of source code used. Apart from using the oracle db, the text presents an example of MySql db server and Eclipse too. The applications are usually tested and deployed to the Weblogic server version 10.1.x.x. g  via ant scripts.
On the dark side the source code consists of orphan files, neither ears, nor whole JDeveloper workspaces; as it is usual in oracle university courses solutions. Moreover, the code seems to be what is printed in the text and has some errors. For example: in chapter 2, on page 33 the  modified ejb-jar.xml deployment descriptor reads like this:

<ejb-ql>
<![CDATA[SELECT OBJECT(a) FROM CatalogBean AS a WHERE a.catalogId = ?1
</ejb-ql>

meaning that the <![CDATA[ tag is not closed properly, as it is easily understood when these lines are pasted to the editor window. In chapter 4,in CatalogTestSessionEJBBean the method is not persistEntity(catalog), but persistCatalog(catalog) and so on. After some investigation or debugging, one persistent reader will probably end up with a working application.  A mistake which occurs numerous times is the number 2 missing from any sql statement with a VARCHAR2 datatype.  Therefore, it seems that gathering the source code of the book was maybe only an afterthought.  Furthermore, some screenshots and relevant text instructions, apply only to older versions of JDeveloper, other than the current 11.1.2. More advanced topics such as tuning, are beyond the scope of this book.

All in all, the text could be a valuable introduction to combining ejb 3 and fusion for JDeveloper funs. This is recommended for zealots of ADF business components, in order to compare both model tier technologies, especially performance. As it was written back in 2010, ejb technology has somehow superceded it. Thus, if you are a Netbeans fun, you will probably think that is an obsolete book. However, the current JDeveloper version does not seem to support ejb 3.01, so to loyal JDevepoper fanatics, it won't make any difference at all!

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