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Sunday, May 27, 2012

Java: Why JavaBeans?

Ok dears here is a short description about Java Beans as there is a confusion of using it as commented on blog "JavaBean enhancements in Java 7"

The official definition of a bean, as given in the JavaBeans specification, is:
"A bean is a reusable software component based on Sun's JavaBeans specification that can be manipulated visually in a builder tool."
Once you implement a bean, others can use it in a builder environment (such as NetBeans). Instead of having to write tedious code, they can simply drop your bean into a GUI form and customize it with dialog boxes.

I'd like to address a common confusion before going any further: The JavaBeans that we discuss in this chapter have little in common with Enterprise JavaBeans (EJB). Enterprise JavaBeans are server-side components with support for transactions, persistence, replication, and security. At a very basic level, they too are components that can be manipulated in builder tools. However, the Enterprise JavaBeans technology is quite a bit more complex than the "Standard Edition" JavaBeans technology.

That does not mean that standard JavaBeans components are limited to client-side programming. Web technologies such as JavaServer Faces (JSF) and JavaServer Pages (JSP) rely heavily on the JavaBeans component model.

Why Beans?
Programmers with experience in Visual Basic will immediately know why beans are so important. Programmers coming from an environment in which the tradition is to "roll your own" for everything often find it hard to believe that Visual Basic is one of the most successful examples of reusable object technology. For those who have never worked with Visual Basic, here, in a nutshell, is how you build a Visual Basic application:
  1. You build the interface by dropping components (called controls in Visual Basic) onto a form window.

  2. Through property inspectors, you set properties of the components such as height, color, or other behavior.

  3. The property inspectors also list the events to which components can react. Some events can be hooked up through dialog boxes. For other events, you write short snippets of event handling code.

I do not want to imply that Visual Basic is a good solution for every problem. It is clearly optimized for a particular kind of problem—UI-intensive Windows programs. The JavaBeans technology was invented to make Java technology competitive in this arena. It enables vendors to create Visual Basic-style development environments. These environments make it possible to build user interfaces with a minimum of programming.