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Screenshot Core Java 2: Volume I - Fundamentals

Table of Contents
 1.  An Introduction to Java


A Short History of Java

This section gives a short history of Java's evolution. It is based on various published sources (most importantly, on an interview with Java's creators in the July 1995 issue of SunWorld's on-line magazine). Java goes back to 1991, when a group of Sun engineers, led by Patrick Naughton and Sun Fellow (and all-around computer wizard) James Gosling, wanted to design a small computer language that could be used for consumer devices like cable TV switchboxes. Since these devices do not have a lot of power or memory, the language had to be small and generate very tight code. Also, because different manufacturers may choose different central processing units (CPUs), it was important not to be tied down to any single architecture. The project got the code name "Green." The requirements for small, tight, and platform-neutral code led the team to resurrect the model that some Pascal implementations tried in the early days of PCs. What Niklaus Wirth, the inventor of Pascal, had pioneered, and UCSD Pascal did commercially, was to design a portable language that generated intermediate code for a hypothetical machine. (These are often called virtual machines—hence, the Java Virtual Machine or JVM.) This intermediate code could then be used on any machine that had the correct interpreter. The Green project engineers used a virtual machine as well, so this solved their main problem. The Sun people, however, come from a UNIX background, so they based their language on C++ rather than Pascal. In particular, they made the language object-oriented rather than procedure oriented. But, as Gosling says in the interview, "All along, the language was a tool, not the end." Gosling decided to call his language "Oak." (Presumably because he liked the look of an oak tree that was right outside his window at Sun.) The people at Sun later realized that Oak was the name of an existing computer language, so they changed the name to Java. In 1992, the Green project delivered its first product, called "*7." It was an extremely intelligent remote control. (It had the power of a SPARCstation in a box that was 6 inches by 4 inches by 4 inches.) Unfortunately, no one was interested in producing this at Sun, and the Green people had to find other ways to market their technology. However, none of the standard consumer electronics companies were interested. The group then bid on a project to design a cable TV box that could deal with new cable services such as video on demand. They did not get the contract. (Amusingly, the company that did was led by the same Jim Clark who started Netscape—a company that did much to make Java successful.) The Green project (with a new name of "First Person, Inc.") spent all of 1993 and half of 1994 looking for people to buy its technology—no one was found. (Patrick Naughton, one of the founders of the group and the person who ended up doing most of the marketing, claims to have accumulated 300,000 air miles in trying to sell the technology.) First Person was dissolved in 1994. While all of this was going on at Sun, the World Wide Web part of the Internet was growing bigger and bigger. The key to the Web is the browser that translates the hypertext page to the screen. In 1994, most people were using Mosaic, a noncommercial Web browser that came out of the supercomputing center at the University of Illinois in 1993. (Mosaic was partially written by Marc Andreessen for $6.85 an hour as an undergraduate student on a work-study project. He moved on to fame and fortune as one of the cofounders and the chief of technology at Netscape.) In the SunWorld interview, Gosling says that in mid-1994, the language developers realized that "We could build a real cool browser. It was one of the few things in the client/server mainstream that needed some of the weird things we'd done: architecture neutral, real-time, reliable, secure—issues that weren't terribly important in the workstation world. So we built a browser." The actual browser was built by Patrick Naughton and Jonathan Payne and evolved into the HotJava browser. The HotJava browser was written in Java to show off the power of Java. But the builders also had in mind the power of what are now called applets, so they made the browser capable of executing code inside web pages. This "proof of technology" was shown at SunWorld '95 on May 23, 1995, and inspired the Java craze that continues unabated today. Sun released the first version of Java in early 1996. People quickly realized that Java 1.0 was not going to cut it for serious app development. Sure, you could use Java 1.0 to make a nervous text applet that moves text randomly around in a canvas. But you couldn't even print in Java 1.0. To be blunt, Java 1.0 was not ready for prime time. Its successor, version 1.1 filled in the most obvious gaps, greatly improved the reflection capability, and added a new event model for GUI programming. It was still rather limited, though. The big news of the 1998 JavaOne conference was the upcoming release of Java 1.2, which replaced the early toy-like GUI and graphics toolkits with sophisticated and scalable versions that come a lot closer to the promise of "Write Once, Run Anywhere" than their predecessors. Three days after (!) its release in December 1998, Sun's marketing department changed the name to the catchy term Java 2 Standard version Software Development Kit Version 1.2. Besides the "Standard version," two other versions were introduced: the "Micro version" for embedded devices such as cell phones, and the "Enterprise version" for server-side processing. This tutorial focuses on the Standard version. Versions 1.3 and 1.4 of the Standard version are incremental improvements over the initial Java 2 release, with a number of new features, increased performance and, of course, quite a few bug fixes. Table 1-1 shows the growth of the Java app coding interface (API) over the years. As you can see, the size of the API has grown tremendously.:

Table 1-1. The Growth of the Java Standard version API

Version

Number of classes and interfaces

Number of methods and fields

1.0

212

2125

1.1

504

5478

1.2

1781

20935

1.3

2130

23901

1.4

3020

32138

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