Beyond HTML: Tools for Interactivity

Tool #5: Java

Sun Microsystem’s Java platform is actually much more than a programming language.  It allows you to use the same application from any kind of machine—PCs, Macs, handheld “palmtops,” even the increasingly popular Internet phones. Two of the most visible examples of Java technology-based software today are on enterprise networks, and on the Internet. One of these examples are the interactive programs are called "applets," which run right on your local browser (client side) as nearly independent applications. The second example of Java is the server-side Java technology of servlets, which can be as simple as embedded code in HTML pages (called JSP pages, which function similarly to Cold Fusion, ASP and PHP) to full-scale Java Enterprise software, based on their J2EE (Java 2 Enterprise Edition) standards, which can interconnect all facets of a business to the web.

Browser Support

• Most popular browsers incorporate support for Java applets, and for those that do not, a free, universal Java plug-in is available from Sun.
• Server-side Java is fully independent of any browser limitations.

What can Java do?

1. Java applets can provide any interactivity you can do with CGI/Perl scripting, JavaScript, Cold Fusion, and then some! Results are limited only by the creativity and programming knowledge of the applet's developer. Applets can provide more sophisticated interactive graphics and other interactive elements than possible with any of the other tools:
   
   An example of sophisticated an interactive 3d graphics applet:
   http://www.frontiernet.net/~imaging/java3dviewer.html
   
   From the UVa Alumni page, a Java applet running a Lawn webcam:
   http://www.virginia.edu/cgi-local/rcamcgi
   
   Break yourself of your lottery habit with the Java lottery calculator:
   http://www.cadenhead.org/book/java2412/lottomad.shtml
   
   
2. Server-side Java is behind many of the large enterprise sites on the web, which integrate multiple systems, applications and databases into a seamless web "portal".
   
   Delta.com is powered by the BEA WebLogic J2EE (Java 2 Enterprise Edition) software, and incorporates multiple internal and external databases and applications within it's deceptively simple web interface:
   http://www.delta.com/home/index.jsp

Pitfalls

• Java is not for beginners. Previous experience programming or scripting is helpful for picking up Java programming concepts from the web or from a book or manual. . A better strategy is to enroll in a course in Java (see Java Resources below). Although Java has a higher learning curve than some of these other technologies, it is also more powerful and ultimately more flexible.

Effect on System Performance

• Applets can take time to load into client's browser.
  

Java Resources

1. Everything from a very approachable article on “What is Java” to advanced tips from the experts is available at Sun Microsystem’s flagship Java site:
   http://java.sun.com
   
   
2. Another resource to begin “from the ground up” is at Webdeveloper.com:
   http://webdeveloper.internet.com/java/java_programming_grounds_up.html

 

End of Course!
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Introduction | Tool Types
JavaScript | DHTML | CGI/Perl | Cold Fusion | Java