On 11 Jul 2007, at 9:56 pm, Bulat Ziganshin wrote:Java comes close to being competition, but it's slow and eats memory
never checked it myself, but people say that modern Java implementations are as fast as C# and close to C++ speeds
People will say anything, but before believing this particular one you will have to do your own measurements. Here's mine: I'm one of two lecturers in a 4th year information retrieval paper. The main programming exercise is one where the students write their own simple IR engine. It's really pretty simple. My model answer in C is two separate programs, an index builder and a query engine, and is 804 SLOC in 1075 total lines. Each year, despite our advice, some student does it in Java. I have one such from last year: 1611 SLOC in 2531 total lines. (Yes, this does mean programmer X writing C can be twice as productive as programmer Y writing Java.) The real killer is performance: the Java program is 150 times slower than the C one. Let me say that slowly: one hundred and fifty times slower. What was that about "close to C++ speeds" again? The reason I have the program is that the student was distressed by this and wanted me to help. The problem was the Java libraries, one class in particular. By replacing that class with home brew code (at the cost of several days coding and experimenting) it was possible to speed the Java program up by a factor of about 15, at which point it was *still* slower than AWK (using 'mawk 1.3.3'). I mentioned this in another context, and got a reply from someone who has worked on large commercial projects in Java, who said that typically half of their code was application-specific and half of it was rewrites of Java library facilities to work around serious performance problems. The lesson here is that productivity and performance are NOT solely a matter of language; they are also a matter of libraries. The Haskell language is wonderful and I enjoy experiencing the reality of "there is nothing as practical as a good theory". But if we just had the Haskell 98 report and libraries, it would NOT be a productive tool for many real problems. The growing collection of amazing stuff in the hackage collection is extremely important.