You can notice internet applications everyplace on the web. Many of those internet applications area unit accustomed method on-line forms, tally selection polls, obey among online stores, enable users to book a flight for his or her next business trip, or just to show the user's login name. Which Java technologies do one got to produce an online application and that packages do one got to import? The answer depends on what quite an application you are building and what it will. This article provides an outline of the Java technologies concerned in making varied styles of internet applications, tells you after you would possibly attempt to use them, and provides links to get you started.Future articles can cowl the way to use these technologies in building internet applications. To use the technologies represented during this article, transfer Java Development Kit (JDK) 5.0 Update 9 with Java Platform, Enterprise Edition (Java EE) or later and install it on your computer. Before you start secret writing, you would like to know what an online application is, what Java technologies area unit accessible to be used, and what development tools will prevent time and build creating applications easier. What Is a Web Application? Web applications area unit naturally distributed applications, which means that they're programs that run on everyone laptop and communicate through a network or server. Specifically, net applications area unit accessed with an online browser and area unit well-liked due to the benefit of victimization the browser as a user consumer. For the enterprise, the flexibility to update and maintain net applications while not deploying and putting in a package on doubtless thousands of consumer computers may be a key reason for his or her quality. Web applications area unit used for net mail, online retail sales, discussion boards, weblogs, online banking, and more. One net application may be accessed and employed by a lot of folks. Like desktop applications, web applications are made up of many parts and often contain mini programs, some of which have user interfaces, and some of which do not require a graphical user interface (GUI) at all. In addition, net applications oftentimes need a further markup or scripting language, such as HTML, CSS, or JavaScript programming language. Also, several applications use solely the Java programing language, which is ideal because of its versatility. A web application may be as straightforward as a page that shows this date and time or as complicated as a collection of pages on that you'll be able to look up and book the foremost convenient flight, hotels, and automobile rentals for your next vacation. Java Technologies to Use in Web Applications There are too several Java technologies to list in one article, thus this text can describe solely those most often used. The number of technologies listed here will seem overwhelming. Keep in mind that you will not need to use them all. In fact, an online application typically consists of nothing quite one page created with the JavaServer Pages (JSP) technology. Sometimes you may mix 3 or a lot of such technologies.No matter what percentage you finish up exploitation, it's good to know what is available to you and how you can use each one in a web application. Java Servlet API The Java Servlet API permits you to outline HTTP-specific categories. A servlet category extends the capabilities of servers that host applications that are accessed by means of a request-response programming model. Although servlets will reply to any style of a request, they are commonly used to extend the applications hosted by web servers. For instance, you might use a servlet to get the text input from an online form and print it back to the screen in an HTML page and format, or you could possibly use a unique servlet to write down the info to a file or info instead. A servlet runs on the server aspect, while not an application user interface or hypertext markup language programme (UI) of its own.Java Servlet extensions make many web applications possible. JavaServer Pages Technology JavaServer Pages (JSP) technology provides a simplified, quick thanks to producing dynamic online page.JSP technology permits fast development of web-based applications that square measure server and platform independent.JSP technology enables you to add snippets of servlet code directly into a text-based document. Typically, a JSP page is a text-based document that contains two types of text: Static data, which can be expressed in any text-based format, such as HTML, Wireless Markup Language (WML), or XML JSP technology elements, which determine how the page constructs dynamic content. The packages involved in creating JSP pages are javax.el, javax.servlet.jsp,javax.servlet.jsp.el,and javax.servlet.jsp.tagext, though you will rarely have to import these directly. A JSP page can be as simple as a bit of HTML with one snippet of JSP code and the .jsp extension of the page name. For instance, you can create a web site of JSP technology pages that use one snippet of code to include the header.html file, which contains the site navigation. This way, when you change a link to a button in the navigation, you make the change in only one file, and that file loads into all the pages on the site that have this code snippet: <%@ include file="header.html" %> That line of code works very much like a server-side include if you are familiar with those. Because this web page is now a JSP page, you could also go on to add more Java technology code to create dynamic web content, such as polls, forms, ways to enter or retrieve data from a database, and so forth.