Former JavaSoft programmer Dave Brown has never regretted going crazy over Java during the summer of 1995. One night a friend turned him on to the Java web site. "I downloaded the browser and immediately started writing my own applet," he says, proudly. "I was hooked, and that winter I came out to work for Sun."

Brown's work at JavaSoft focused on two classes in the JDK package: java.net and java.io. What's the difference between the two sets? Brown explains; java.net is reading and writing to other computers on the network. It will allow you to read URLs from the WWW. The I/O classes deal with reading and writing files from a local disk," Brown continues. "You read files such as word-processing documents from your computer, workstation, or Mac. If you wrote a word-processing application in Java, it would look at documents from the local disk and store it to the local disk."

For those new to the term "class," Brown explains it better than anyone in the business: "Java is an object-oriented language. Every object has a type. The type of an object is its class. A class is a description of what constitutes that object and what you can ask it to do. Different classes represent different things in programming."

And that's that.

If Brown seems well-versed in the art of programming--it's not surprising, the boy genius got his graduate degree from Columbia. What inspires him? "Knowing that the software I write is used by more people than I could probably count," he says.

JDC: What's the class structure comparison between the JDK and other Java products?

DB: I think JDK is unparalleled. There's no reasonable competition. As far as a cross-platform set of libraries, it's more comprehensive than any other class library that you could purchase anywhere.

JDC: What's the best part of this new and improved Java class structure?

DB: Java's new class structure has runtime type checking. When you're programming, Java interpreters will recognize if it's the wrong type.

JDC: What's the strategy behind the class project?

DB: The most important goal is to ensure that the APIs work robustly. The second goal is to make sure that they work the same on each program.

JDC: What is the coolest thing about Java?

DB: Networking the APIs of Java, and how simply and compactly you can make computers talk to each other by programming in Java. What does that mean? Most networking applications can be done in Java with the fraction of what it would take to do it in C, primarily because it's so much easier to understand and faster to develop. It has cross-platform portability, and it's simply the programming language for the Internet.

JDC: How important is Java and its class structure?

DB: The development of ubiquitous computer networks is a huge development in computer science in general. Being able to extract information from millions of computers across the world is incredibly powerful. The fact that Java is written once and runs on all of these computer platforms is also powerful.

JDC: What does Java mean to Microsoft?

DB: Windows 95 is the most ubiquitous operating system out there. But Java, because it's so nice to program in, and because it runs on all platforms, means that Microsoft's stranglehold on the market might begin to deteriorate. Java is simply a nicer language to program in, and that means people won't be developing in Microsoft Foundation Classes.

JDC: What does Java mean to Macintosh?

DB: When Macintosh gets Java working on it, it should give them new life--I would hope. When the new Java programs come on the market--if they run well on the Macintosh--people will have the impetus to buy a Mac.

JDC: What's a mistake beginner programmers should avoid at all costs, especially when working in class structure?

DB: One thing to avoid is to begin writing a program without clearly establishing a design for what you want to do. It means more work and revision later. Planning and designing are most of the development process. I would advise not to forgo a design in haste.

JDC: What's a mistake programmers need to make to get better?

DB: My advice is not unique to Java. To do anything well and efficiently in life, it's best to have things planned out with a clear goal in mind. That was one mistake I learned. When you start implementing something without planning it out or designing it well, you have to redo it. That's a painful process.

JDC: What's the best resource for Java programmers?

DB: A computer in a quiet place without distraction, and a copy of JavaSoft's JDK. Enthusiasm and patience are also vital.

JDC: What's the future of Java?

DB: The future of Java is Java developers. Java already has a tremendous amount of momentum. The more people who use it, the more important it becomes. I can't imagine writing software in anything other than Java; it's nothing short of a revolution in software development. The continued effort to augment and fix JDK's convenient building blocks will be critical to Java's continued success.

JDC: What's your specialty?

DB: Working on the networking stuff and on the guts of the virtual machine. The Java interpreter is the virtual machine, and it interprets Java code into bit code.

JDC: What's your most cherished programming tip?

DB: Java is a multithreaded programming language. And one of the primary primitives for synchronizing different threads in a program is the synchronized keyword. And by making a Java method synchronized, one thread can execute the method at any given time.

But the mistake I've seen is overusing synchronized, instead of leaving things unsynchronized. In a typical program, only a small fraction, if any, of the methods need to be synchronized and by gratuitously doing it, you create problems. You slow down your program. You also make it more error-prone by opening up the possibility that two threads are trying to enter and then neither one can proceed. In short, use synchronized only when needed.

JDC: What are some interesting Java developments or particularly great uses of Java?

DB: WebCrawler uses Java to index a whole collection of web sites. When you point to a page on the World Wide Web, it finds the links that page points to, stores information, and follows those links. It's easy to program something like this in Java. Another neat Java development is the Java Operating System; its advent proves that Java is a general-purpose programming language, and you can do a lot more than write applets with it.

A Simple, Multithreaded Web Server