Preface

I suggested to my brother Todd, who is making the leap from hardware into programming, that the next big revolution will be in genetic engineering.

We'll have microbes designed to make food, fuel, and plastic; they'll clean up pollution and in general allow us to master the manipulation of the physical world for a fraction of what it costs now. I claimed that it would make the computer revolution look small in comparison. Feedback

Then I realized I was making a mistake common to science fiction writers: getting lost in the technology (which is of course easy to do in science fiction). An experienced writer knows that the story is never about the things; it's about the people. Genetics will have a very large impact on our lives, but I'm not so sure it will dwarf the computer revolution (which enables the genetic revolution)—or at least the information revolution. Information is about talking to each other: yes, cars and shoes and especially genetic cures are important, but in the end those are just trappings. What truly matters is how we relate to the world. And so much of that is about communication. Feedback

This book is a case in point. A majority of folks thought I was very bold or a little crazy to put the entire thing up on the Web. "Why would anyone buy it?" they asked. If I had been of a more conservative nature I wouldn't have done it, but I really didn't want to write another computer book in the same old way. I didn't know what would happen but it turned out to be the smartest thing I've ever done with a book. Feedback

For one thing, people started sending in corrections. This has been an amazing process, because folks have looked into every nook and cranny and caught both technical and grammatical errors, and I've been able to eliminate bugs of all sorts that I know would have otherwise slipped through. People have been simply terrific about this, very often saying "Now, I don't mean this in a critical way..." and then giving me a collection of errors I'm sure I never would have found. I feel like this has been a kind of group process and it has really made the book into something special. Because of the value of this feedback, I have created several incarnations of a system called "BackTalk" to collect and categorize comments. Feedback

But then I started hearing "OK, fine, it's nice you've put up an electronic version, but I want a printed and bound copy from a real publisher." I tried very hard to make it easy for everyone to print it out in a nice looking format but that didn't stem the demand for the published book. Most people don't want to read the entire book on screen, and hauling around a sheaf of papers, no matter how nicely printed, didn't appeal to them either. (Plus, I think it's not so cheap in terms of laser printer toner.) It seems that the computer revolution won't put publishers out of business, after all. However, one student suggested this may become a model for future publishing: books will be published on the Web first, and only if sufficient interest warrants it will the book be put on paper. Currently, the great majority of all books are financial failures, and perhaps this new approach could make the publishing industry more profitable. Feedback

This book became an enlightening experience for me in another way. I originally approached Java as "just another programming language," which in many senses it is. But as time passed and I studied it more deeply, I began to see that the fundamental intention of this language was different from other languages I had seen up to that point. Feedback

Programming is about managing complexity: the complexity of the problem you want to solve, laid upon the complexity of the machine in which it is solved. Because of this complexity, most of our programming projects fail. And yet, of all the programming languages of which I am aware, none of them have gone all-out and decided that their main design goal would be to conquer the complexity of developing and maintaining programs.^[1] Of course, many language design decisions were made with complexity in mind, but at some point there were always some other issues that were considered essential to be added into the mix. Inevitably, those other issues are what cause programmers to eventually "hit the wall" with that language. For example, C++ had to be backwards-compatible with C (to allow easy migration for C programmers), as well as efficient. Those are both very useful goals and account for much of the success of C++, but they also expose extra complexity that prevents some projects from being finished (certainly, you can blame programmers and management, but if a language can help by catching your mistakes, why shouldn't it?). As another example, Visual BASIC (VB) was tied to BASIC, which wasn't really designed to be an extensible language, so all the extensions piled upon VB have produced some truly horrible and unmaintainable syntax. Perl is backwards-compatible with Awk, Sed, Grep, and other Unix tools it was meant to replace, and as a result is often accused of producing "write-only code" (that is, after a few months you can't read it). On the other hand, C++, VB, Perl, and other languages like Smalltalk had some of their design efforts focused on the issue of complexity and as a result are remarkably successful in solving certain types of problems. Feedback

What has impressed me most as I have come to understand Java is that somewhere in the mix of Sun's design objectives, it appears that there was the goal of reducing complexity for the programmer. As if to say "we care about reducing the time and difficulty of producing robust code." In the early days, this goal resulted in code that didn't run very fast (although there have been many promises made about how quickly Java will someday run) but it has indeed produced amazing reductions in development time; half or less of the time that it takes to create an equivalent C++ program. This result alone can save incredible amounts of time and money, but Java doesn't stop there. It goes on to wrap many of the complex tasks that have become important, such as multithreading and network programming, in language features or libraries that can at times make those tasks easy. And finally, it tackles some really big complexity problems: cross-platform programs, dynamic code changes, and even security, each of which can fit on your complexity spectrum anywhere from "impediment" to "show-stopper." So despite the performance problems we've seen, the promise of Java is tremendous: it can make us significantly more productive programmers. Feedback

One of the places I see the greatest impact for this is on the Web. Network programming has always been hard, and Java makes it easy (and the Java language designers are working on making it even easier). Network programming is how we talk to each other more effectively and cheaper than we ever have with telephones (email alone has revolutionized many businesses). As we talk to each other more, amazing things begin to happen, possibly more amazing even than the promise of genetic engineering. Feedback

In all ways—creating the programs, working in teams to create the programs, building user interfaces so the programs can communicate with the user, running the programs on different types of machines, and easily writing programs that communicate across the Internet—Java increases the communication bandwidth between people. I think that the results of the communication revolution may not be seen from the effects of moving large quantities of bits around; we shall see the true revolution because we will all be able to talk to each other more easily: one-on-one, but also in groups and, as a planet. I've heard it suggested that the next revolution is the formation of a kind of global mind that results from enough people and enough interconnectedness. Java may or may not be the tool that foments that revolution, but at least the possibility has made me feel like I'm doing something meaningful by attempting to teach the language

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