Chapter 2: World Wide Web the Next Generation
"I never think of the future. It comes soon enough." -Albert Einstein
On the Web, the next generation is rapidly approaching. It is in fact, constantly evolving. This chapter profiles a few of the exciting developments on the horizon.
2 . 1 Java/HotJava
In the overheated realm of the Web, it is probably accurate to characterize Sun Microsystems' Java as the white hot leader of the pack. Simply put Java, brings action to the Web, which currently consists of inactive, static document elements. First, let's clarify some terms.
Java is a new computer language. HotJava is a Web browser implemented in Java.(1) According to Bill Joy, co-founder of Sun, Java is "C++ done right". Java is an interpreted language. Little chunks of Java code are sent through the net to the browser and when appropriate they execute, right there on the user's machine. Those little chunks of code are called applets. In current Web browsers, text, graphics, and sounds just sit there. Applets can make the graphics animate, the sounds play, and the text move.
According to the Sun White Paper on Java, Java is(2):
"Java: A simple, object-oriented, distributed, interpreted, robust, secure, architecture neutral, portable, high-performance, multithreaded, and dynamic language."
This is a mouthful any way you slice it. However, the body of the white paper is interestingly written and goes on to explain the relevance of each of the admitted buzz words to Java.
Java's result is the ability to interact with graphics, sounds, and text in new and compelling ways. For example, a cube appearing on the Web document page can be spun around, a button will detect the presence of a cursor, buttons can highlight when a cursor is near, and image maps can show you where those invisible hot spots really are. To take one example: a HotJava page contains a stock market ticker tape with some animated strip charts and a dynamically updated table. (3)
The toolkit you use to develop Java applets is called the Java Development Kit (JDK). The JDK includes a nice utility called the appletviewer. The appletviewer takes an HTML file as its input and runs the Java applet. You don't have to be on-line. It is very convenient.
The Applet Viewer running a sample applet.
Java also addresses many of the problems of portable code. Because it is an interpreted language you simply port a Java interpreter to a particular hardware platform. Most Java code, and the applications should run on that platform. This technique is not new; UCSD Pascal, Smalltalk, and Lisp have used the same idea in the past. As soon as HotJava browsers appear on different computing platforms, the applet Java code can be executed on those platforms.
The interpreted nature of Java also allows the HotJava Web browser to adapt new data types on the fly. If a new sound or video compression format sweeps the Net, Javabased browsers will be able to adapt rather than being upgraded. The HotJava White Paper describes this capability:(4)
HotJava's dynamic behavior is also used for understanding different types of objects. For example, most Web browsers can understand a small set of image formats (typically GIF, X11 pixmap, and X11 bitmap). If they see some other type, they have no way to deal with it directly. HotJava, on the other hand, can dynamically link the Java code from the host that has the image, allowing it to display the new format. So, if someone invents a new compression algorithm, the inventor just has to make sure that a copy of the Java code is installed on the server that contains the images the inventor wants to publish. All the other browsers in the world will have to be upgraded to take advantage of the new algorithm. HotJava upgrades itself on the fly when it sees this new type.
Netscape includes a Java interpreter with its secondgeneration browser. Microsoft has also licensed Java for use with its Web browser, the Internet Explorer. Sun wisely decided to open up its technology to all rather than put yet another browser out onto the Net.
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