GWT exception : Deferred binding result type should not be abstract Or Rebind result must be a class

In GWT, when you get this error in hosted mode
Deferred binding result type should not be abstract
or
The following error while compiling
Rebind result must be a class

most likely you have forgot to extend your business interface from RemoteService. Therefore GWT engine is trying to instantiate the interface itself. That is , instead of

@RemoteServiceRelativePath("relativeServicePath")
    public interface BusinessInterface extends RemoteService

you have written

@RemoteServiceRelativePath("relativeServicePath")
    public interface BusinessInterface

Beginning Groovy and Grails

In the last session on April 13, 2009 on Jazz and Rational Team Concert at TCJUG , I have won the book Beginning Groovy and Grails: From Novice to Professional (Beginning from Novice to Professional) in the lucky draw.

This is happening second time in the row that I have attended JUG meeting with Groovy message. In my last meeting the topic of discussion itself was groovy and this time around, it is the book. The message is loud and clear. Looks like everyone has started taking Groovy seriously. People consider it as gen-next Java language. After all, Groovy is not something which poises itself to compete with Java language. In fact it builds itself over the Java language. You run groovy programs on JVM. While relieving developers of many of the pains which comes with java, groovy provides many powerful features, missing and long sought in Java.
Having said that, I am still a doubtful thomas, when it comes to new technology. To build a secure, scalable, robust application, I would not put my bets on Grails. At least for now.

By the way the presentation slides for Jazz are not there yet on TCJUG website. Check http://jazz.net/ for more details.
Jazz is also a wonderful framework address the concerns of the entire life-cycle of project development. From requirement analysis to design and development; from testing to maintenance; from project management to project change management; it is built on the vision to provide one -stop- shop for all the needs.
Rational Team Concert is the product built on Jazz framework. The speaker has demonstrated many cool features of RTC. It integrates IDE, testing environment, team collaboration, version and cofiguration management, quality management in the other words absolutely every tool we use daily during the software lifecycle. It integrates all these tools at one place. PM will have the clear and accurate picture what is going on with the status and updates of each and every developer, tester will now what fixes developers are working on etc etc. Worth checking out. As far as I remember, the speaker said that this product is relatively new but it has achieved record sales in its category in IBM.

Rules within an Enterprise and their management with a BRMS, focus on JRules

I have attended a very nice session at TCJUG back in November 2008( I know I am very late in reporting that).

The speaker DJ Des Jardins made a very strong case for JRules. While there are many open source rule engines available in the market like Drools, JRules stands apart from all those because of its capabilities. If you see the presentation available at the site you can judge by yourself that JRules is simply superior compared to other rule engines when it comes to customization, options and flexibility. Check that out.

However, the slides are not very elaborate. To appreciate the full capabilities of JRules you may want to try it once.

Groovy – Hype or Hope?

Last week I have attended a Java User Group meeting in Bloomington, MN. The speaker Mark Rausch made a solid case for Groovy as the gen-next application.
He talked about how Java Scripting recognizes the “pain points” of the Java Developer community.
Learning Groovy and using is not difficult at all. Unlike other languages which force you to learn new syntax or think Class and objects differently, Groovy is Java. In fact, you have been writing Groovy all along. If you rename .java file to .groovy, it is a compilable groovy program.
Learning it and using it is very easy because of the smooth learning curve. It is worth trying. I will soon write (Really Simple) steps to write your first groovy program.

(Really) Simple Steps to write GWT app

(Really) Simple Steps to use myfaces and facelets in JSF based app

Coming soon

(Really) Simple Steps to create Ajax app using DWR and Spring

Coming soon.

(Really) Simple Steps to write WebServices using AXIS

Coming Shortly

Beautiful Architecture

I have received this book from one of the Java User group meeting I attended on Tuesday April 7, 2009. I have gone through the first chapter and reviews on amazon and it looks like an interesting book.
It’s always nice to know the views of leading architects on wide variety of topics

Hibernate Query Cache

Hibernate provides sophisticated caching mechanisms to improve the performance. Apart from
First-level, Second-Level and query cache, Hibernate can be configured to make use of some open source cache solutions like EHCache or JBoss Cache etc.

If your Hibernate query yields huge but similar results every time it is executed, it is a good idea to cache the results in hibernate to improve the performance. This could be achieved by first enable the hibernate query cache in the hibernate configuration
in properties file

hibernate.cache.use_query_cache true

or xml configuration file like

<property name="hibernate.cache.use_query_cache">true</property>

and while executing the query specify the cacheability like this

sess.createQuery("from.......")
    .setCacheable(true)
    .list();