Seibel: Do you feel at all that programming is a young person’s game?

Eich: I think young people have enormous advantages, just physiological advantages to do with the brain. What they don’t have is the wisdom! You get crustier and maybe you get slower but you do learn some painful lessons that you try to pass on to the next generation. I see them ignoring me and learning them the hard way, and I shake my fist!

But, apart from that, if you stay well-read and keep at it, your output doesn’t necessarily have to be voluminous. While producing a lot of code is still important, what has interested me—and this is something that we talked about at Netscape when we talked about their track for principal engineer—is somebody who isn’t management but still has enough leadership or influence to cause other programmers to write code like they would write without them having to do it, because you don’t have enough hours in the day or fingers.

Having that ability to spread your approach and whatever you’ve learned about programming, and have that go through some kind of community and produce a corpus of code that’s bigger than you could do, that’s as satisfying to me as being the one that stays up all night writing too much code.

I’m still working too much, plus I’ve got small children. My wife is a good sport but I don’t think she likes me traveling so much. But I’m doing some of that too. That’s not programming, yet it somehow has become important. In the case of JavaScript we have to figure out how to move the language forward, and that requires some amount of not just evangelism, but getting people to think about what would happen if the language did move, how would you like it to move, where should it go. And then dealing with the cacophony of responses.

Not all programmers will say this, a lot of them are solitary, in the corner, but one of the things I realized at Netscape was that I liked interacting with people who actually use my code. And I would miss that if I went back into a corner. I want to be grounded about this. I’m secure enough to think I could go do something that was a fine sky castle for myself, but I’m realist enough to know that it would be only for myself and probably not fine for other people. And what’s the point? “If I’m only for myself”, you know, Hillel the elder, “what am I?”

I am not JavaScript. In the early days, it was such a rush job and it was buggy and then there was some Usenet post Jamie Zawinski forwarded me. He said, “They’re calling your baby ugly.” I have real kids now; I don’t have to worry about that.

Joshua Bloch

Now Chief Java Architect at Google, Bloch previously was a Distinguished Engineer at Sun Microsystems, where he led the design and implementation of the Java Collections Framework introduced in Java 2 and was involved in the design of several language additions in the Java 5 release. He has a BS from Columbia University and a PhD from Carnegie-Mellon University, where he worked on the Camelot distributed transaction processing system, which later became Encina, a product of Transarc, where he was a Senior Systems Designer. He wrote the 2001 Jolt Award–winning book Effective Java and coauthored Java Puzzlers and Java Concurrency in Practice.

As you might expect from someone whose job is to encourage the use of Java at Google, Bloch is a strong advocate of the language. Despite the recent flurry of interest in approaches to concurrency such as Software Transactional Memory or Erlang’s message passing, Bloch thinks Java has “the best approach of any language out there” to concurrency and predicts a resurgence of interest in Java as more and more programmers are forced to deal with programming for machines with multicore CPUs.

Bloch is also a strong advocate of treating programming as API design, and we talked about how that affects his own design process, as well as whether Java has gotten too complex and why picking a programming language is like picking a bar.

Seibel: How did you get into programming?

Bloch: I’m tempted to say it’s in the blood. My dad was a chemist at Brookhaven National Lab. When I was in fourth grade, he took a programming course. Back then, of course, machines were mainframes behind glass windows and you handed your deck of cards to the operator. It wasn’t hands-on, but I was just thrilled by the idea of these electronic computing machines that would do stuff for you. So I learned a little bit of Fortran from him while he was taking that course.

Seibel: This would have been what year?

Bloch: I think it was 1971. The bug didn’t really bite me until a couple years later. And what did it, of course, was timesharing. Long Island had a DECsystem-10, which was shared among all of the schools in Suffolk County. There was another one for Nassau County. It’s amazing how many well-known people got their start on one of those two DECsystem-10s.

Once you have interactivity, the bug bites you. I was programming in BASIC, like everybody else back then, from about 1973 through 1976. That’s when I got seriously into it. The amazing thing is, I still have programs from back then on Teletype paper—that’s the medium that survived—and I look at them and I can sort of see that bits and pieces of my style haven’t changed since then.

Seibel: So what was the first interesting program that you remember writing?

Bloch: Well, I remember on July 4th, 1977 writing a version of the classic Twenty Questions game called “animals.” The program had a binary tree with yes-or-no questions at the interior nodes and animals at the leaves. When it first encountered a new animal, it “learned” the animal by asking the user for a yes-or-no question to distinguish the new animal from the one it had incorrectly guessed. The binary tree was stored on disk so the program kept getting “smarter” over time.

I remember thinking, “My gosh, this is cool: the program actually learns.” That was one sort of aha! moment for me. Another thing I remember was in high school—10th grade, I think—on that DECsystem-10. We weren’t allowed to write what would now be called instant-messaging programs—they were thought to be too big a drain on system resources.

Seibel: As they are, in fact, now.

Bloch: Don’t get me started. IM ruins my life. No, email ruins my life—IM is just a distraction. Anyway, being the bratty kid that I was, I entered a project into the Long Island Math Fair on what I called “inter-job communication programs.” I actually won a prize for it.

Seibel: And you actually wrote the programs?

Bloch: Yes. I wrote the programs, except for one that was contributed by a friend named Thomas De Bellis. The unique thing about Tom’s program was that it was written entirely in BASIC. It was line-oriented, and used files to communicate. It wasn’t fast or efficient, but it worked! I wrote two, one line-oriented and one character-oriented. I wrote them in MACRO-10, the PDP-10 assembly language. They used a kind of shared memory called the “high segment” for the communication.

I didn’t know anything about concurrent programming back then. I remember not really understanding mutexes. But there were communication buffers, and independent agents trying to communicate with each other concurrently. So there were race conditions, and occasionally the program lost a character or two. I wasn’t able to figure that out myself as a high-school student.

Seibel: You say that you saw aspects of your current style in your earliest programs. What are the bits that have stayed the same?

Bloch: My attempts to make my programs readable. As Knuth would say, a program is essentially a work of literature. For whatever reason, I realized even back then that a program has to be readable. And that hasn’t changed.