When will Java go mainstream like Python?

Mensanator mensanator at aol.com
Fri Feb 26 02:00:32 CET 2010


On Feb 25, 6:41 pm, "Alf P. Steinbach" <al... at start.no> wrote:
> * Chris Gray:
>
> > Lawrence D'Oliveiro <l... at geek-central.gen.new_zealand> writes:
>
> >> In message <op.u8nfpex8y5e8ok at laptopwanja>, Wanja Gayk wrote:
>
> >>> Reference counting is about the worst technique for garbage collection.
> >> It avoids the need for garbage collection. It means I can write things like
>
> > I'm by no means an expert, but how does reference counting deal with
> > arbitrary long cycles of references (btw I've *written* a simple
> > reference counter for a programming language)?
>
> Generally it doesn't. Some solutions have however been proposed for
> std::shared_ptr in C++. None have made it to any noteworthy status, but they
> demonstrate that there are more or less practical solutions for the most common
> cases.
>
> Currently the upshot is that if you need the kind of self-referential spaghetti
> structure (no offense) created by mathematical expressions that refer to each
> other, then you've passed beyond what can be handled practically by reference
> counting alone or even in combination with cycle handling techniques.
>
> For that you're better off with some functional language, or Python... ;-)
>
> > When I asked someone whose knowlege of Java I trust, he said that modern
> > Java's do both reference counting and garbage collection. That was 2 or 3
> > years ago. I would have guessed that Python was the same.
>
> Yes, Python adds general garbage collection to deal with cycles.
>
> Essentially the reference counting deals efficiently and immediately with
> objects created by expression evaluation, while the general garbage collection
> deals with cyclic structures.
>
> But there's no magic: in particular in Java, Python and like languages you must
> still remember to remove references installed in singletons and globals (e.g.
> for event notifications), otherwise objects will still be referenced and thus
> not garbage collected, causing a memory leak.

Is that really considered a leak, a single instance
of an uncollected global as opposed to a function
that is called millions of times, and each time
it's called creates uncollected temporary variables?

>
> Cheers & hth.,
>
> - Alf




More information about the Python-list mailing list