The Java Developer's kit has a version number that started with 1.0, went through a series 1.0.1, 1.0.2... and then there was 1.1, which introduced major changes. After 1.1.1, 1.1.2,... there was 1.2, which introduced more major changes. Sun must've decided that using the JDK version numbers was confusing, so they introduced the name "Java 2" to mean Java as implemented in JDK 1.2 or later. That's all it means. A JavaBean is a Java "component," like a COM, OLE, or ActiveX component in Win32 programming. The term also is used to refer to EJBs (Enterprise Java Beans) which are components for enterprise applications, meant to be used inside an application server that implements the J2EE (Java 2 Enterprise Environment) standard. A Servlet is also a kind of application component; the idea predates the EJB idea. These days most servlets are HttpServlets -- Java's answer to CGI programs -- i.e., components for Web-based applications.
Thanks for the replied. Well,A bit confused with the component stuff. what's the main usage of the component like javabean?As i'm just learning the java only in the beginning stage. Do u mind to explain more details on the EJB side and J2EE?i'm not quite understand the J2EE stuff. is it a compiler or what? I think i won't touch the Win32 programming again.it's so tough.
Do u mean that the servlet are used for the web page design? Thanks!
author and iconoclast
Servlets are used on the "back end" in web applications. For instance, when you submit a form on a web page, some code, somewhere, may have to insert the values you typed in into a database, and validate your credit card number, etc. If that code is written in Java, it would be in the form of a Servlet. A lot of web sites are powered by Java servlets. EJBs are used in "enterprise" applications, the software that makes big companies operate. The programmer can write only the part specific to the application; the J2EE environment takes care of the stuff that's common to all such applications like networking, data persistence, transactions, replication... if you have no idea what I'm talking about, then don't worry about it for now. When the time comes, you'll need to buy a book (or many books!) on the topic.