[rescue] slow java code...an example of why it might be happening

[Dave McGuire]

   I had originally put this in my other message but it seemed that it 
needed to be separated.

   There's a huge danger of programming in a ridiculously high-level 
language like Java when the programmer don't understand the low-level 
workings of computers.  I suspect that's what's going on here.  Take 
this problem I dealt with a few weeks ago as an oversimplified example. 
  A nicely compartmentalized object which, when instantiated, loads some 
records from a database based on a parameter passed to a constructor.  
The programmer, a guy who started in Java but never learned anything 
lower-level, knew this was how to get one of those objects populated 
with some data from the database.

   Simple, right?  Ok, now he needs to generate about 1800 of these 
objects...so what does he do?  He uses a loop, iterating through the 
array of parameters to pass to the constructor.  If you're tooling 
through your day not thinking too much, and just looking at the object 
as a "black box" without thinking of its innards, this is sorta logical 
I suppose.  It took forever to run.

   The correct solution, of course, is to write a new chunk of code 
which populates an array of objects (or a similar construct) with ONE 
DATABASE QUERY.  The guy just didn't understand why it was so slow, and 
why his methods were wrong, until I drew it out for him on a piece of 
paper...loop iteration, call constructor, do database query, populate 
class variables...loop iteration, call constructor...and so forth.  He 
just didn't understand why this was bad, and more importantly, made no 
connection between this and the fact that it was running too slowly!  
His brain was trained to build an object, then "close the door" on that 
object and completely forget how it works...as long as you remember its 
interface, you can just use it anytime you want.

   There's a such thing as a programming language whose conceptual level 
is TOO HIGH.  This is a big problem with inexperienced programmers.  
Most of the horribly slow and bloated C++ code that I've looked through 
suffers from problems very much like the one I described above, and I 
suspect all the commercial farmed-out-to-India bloatware that you guys 
are bitching about is like this as well.

        -Dave

--
Dave McGuire             "I've grown hair again, just
St. Petersburg, FL           for the occasion."       -Doc Shipley