What Is a Web Application?
Web applications are by nature distributed applications, meaning that they are programs that run on more than one computer and communicate through a network or server. Specifically, web applications are accessed with a web browser and are popular because of the ease of using the browser as a user client. For the enterprise, the ability to update and maintain web applications without deploying and installing software on potentially thousands of client computers is a key reason for their popularity. Web applications are used for web mail, online retail sales, discussion boards, weblogs, online banking, and more. One web application can be accessed and used by millions of people.
A web application can be as simple as a page that shows the current date and time or as complex as a set of pages on which you can look up and book the most convenient flight, hotels, and car rentals for your next vacation.
The Java technologies you’ll use to create web applications are a part of the Java EE platform, in addition to many of the Java Platform, Standard Edition (Java SE) classes and packages. In order for many of these technologies to work on a server, the server must have a container, or web server, installed that recognizes and runs the classes you create. For development and testing of these technologies, you can use the tools detailed in this article, but when you deploy, make sure that the server has Java server software installed to run Java technology-based web applications. If you don’t have access to this information, ask the server administrator.
Java Technologies to Use in Web Applications
There are too many Java technologies to list in one article, so this article will describe only the ones most frequently used. The number of technologies listed here can appear overwhelming. Keep in mind that you will not need to use them all. In fact, a web application often consists of nothing more than one page created with the JavaServer Pages (JSP) technology. Sometimes you will combine three or more such technologies. No matter how many you end up using, it’s good to know what is available to you and how you can use each one in a web application.