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Everything here is my opinion. I do not speak for your employer.
January 2006
February 2006

2006-01-06 »

Observations from my Trip to London

  1. You can't say "Trip to London" without people assuming you mean London, England, even though I actually mean London, Ontario. For some reason this doesn't happen with Waterloo or even, irony of ironies, New England.

  2. The Pontiac Pursuit is the first car I've driven in a long time that continually makes me think "awesome." Apparently due to my complete lack of media input lately, I'd never even heard of it before yesterday. Their web site even talks about its pulsating performance - as if it were a chicken, of all things! I wish I needed a car.

  3. After two days spent essentially in tech support for someone else's product, I now hate programmers even more than ever.

3b. Also, Windows sucks much more than I usually give it credit for.

3c. So does everything else, particularly commercial database servers and anyone who has ever written "sleep(10)" for a "wait for operation to complete" function. I suspect those people are often one and the same.

Java constness and GC

pcolijn wrote about some things he likes/doesn't like in Java. I'm going to disagree with one from each category:

constness: I think you have your inheritence backwards. An immutable instance isn't a subclass of a mutable instance where some operations (gag) throw exceptions by surprise. No, in fact, a mutable instance extends an immutable one. In other words, start with the immutable interface, which only has getThis(), getThat(), etc. From that, derive an interface that adds setThis(), setThat(), etc. People require one of the two interfaces on their objects, and all is well, and you didn't really need const after all. The method you suggested - pretending to implement the mutable interface and then throwing exceptions - is like doing exactly the same thing in C++, and just as evil. On the other hand, in C++, a parent class can talk about a function with "const" whatever, while a child can implement the "non-const" whatever, and things will work sensibly. But if you think about it, that's just the same as what you can do in Java.

Now for the part about Java you do like: garbage collection. I'm actually a big fan of GC as a concept, because the idea of not crashing all the time because of randomly overwriting memory kind of appeals to me. However, I've learned two important things about GC:

1) Not having to explicitly delete things doesn't actually mean you don't have to explicitly think about object deletion; it just makes you think you don't have to think about it, which is much worse. Hence, where C++ programs tend to have explosions, Java programs (seemingly universally) have nasty memory leaks and no good way to find them (because they're not "leaks" in the usual sense; if nobody had a pointer to them anymore, they would be auto-deleted). They also have non-deterministic destructor behaviour, which is very restrictive. A GC language is good as long as people actually think about object lifecycles, but my experience is they don't, and so GC's don't solve anything. (If you think about object lifecycles to the extent that you have to, then you turn out not to need GC because your smart pointers will all do the right thing.)

2) I heard that Java object creation/deletion is so slow that people tend to use "pools" of object types that are created/deleted a lot, and explicitly place those objects into and out of the pools. You know what that is? It's bypassing the GC so you can get explicit memory allocation/deallocation. Snicker. Again, this is nothing against GC specifically (which can be quite fast), but it's definitely a sign that all is not right with the world.

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