Hi ! Yesterday i had an interview. Actually they called me for the second time. Basically they wanted to test me for wireless application development using j2me. This also included core java. I got a little stuck with one question.They asked me the difference in functionality provided by Java Beans( simple worker beans used with JSPs) and EJBs. I told them that both were reusable but simple beans have getter/setter methods while EJBs implement certain interfaces...Actually i've not done any work with EJBs, so i could not satisfy them. If anyone can explan this please do so. Apart from this they asked me a question, i gave the correct answer, but they told me that i was wrong. Then i explanied in detail, how i was right. Later after the interview i checked it from the book and i was right. I was thinking of going back to those guys and showing them the book,but then i thought it won't be of any use. So do you think that i should have gone back to them ? And they also asked me a very idiotic question, which made no sense. Question was that which is subset of the other configuration or profile. I simply told them that it makes no sense to me and if they are trying to confuse me its up to them. They just gave me a smile. Do you think i was right ? Overall the interview went very well.I'm in to j2me for the last 1 year and am currently employed, making wireless apps. I think i was in a commanding position as it was evident from their talk that they did not have much experience with wireless apps. Regards Danish Shaukat
<http://java.sun.com/images/v3_pixel.gif> <http://java.sun.com/products/javabeans/images/javabeans.gif> JAVABEANS FAQ: GENERAL QUESTIONS What is JavaBeans? JavaBeans is a portable, platform-independent component model written in the Java programming language, developed in collaboration with industry leaders. It enables developers to write reusable components once and run them anywhere -- benefiting from the platform-independent power of Java technology. JavaBeans acts as a Bridge between proprietary component models and provides a seamless and powerful means for developers to build components that run in ActiveX container applications. What is a Bean? Why isn't a Bean an Applet? JavaBeans components, or Beans, are reusable software components that can be manipulated visually in a builder tool. Beans can be combined to create traditional applications, or their smaller web-oriented brethren, applets. In addition, applets can be designed to work as reusable Beans. Individual Beans will function quite differently, but typical unifying features that distinguish a Bean are: * Introspection: enables a builder tool to analyze how a Bean works * Customization: enables a developer to use an app builder tool to customize the appearance and behavior of a Bean * Events: enables Beans to communicate and connect together * Properties: enable developers to customize and program with Beans * Persistence: enables developers to customize Beans in an app builder, and then retrieve those Beans, with customized features intact, for future use
Javabeans are basically classes, which support the above. The classes can be used like any other Java class, they just conform to the JavaBeans standard. EJBs, on the other hand, run in the EJB server environment. The are accessed throught interfaces (never directly), and managed by the application server. There are stateless session beans, stateful session beans, entity beans, and message-driven beans, each of which behave differently. EJBs are used to leverage the functionality provided by an EJB server (e.g. failover, transactions). There's more, but that's a rough start to it. Peronsally, I think you should (politely) email them and cite the book, possibly in a follow-up thank you letter. --Mark
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