1/26 Some friends of mine are having problems with memory
management in Java. Is there a way you can force
garbage collection in Java? Alternatively, is their
a way you can do memory allocation similiar to C/C++
where you can explictly allocate and deallocate stuff
so that you aren't at the mercy of the garbage collector?
\_ java 1.1: System.gc(); System.runFinalization;
in that order, to force garbage collection and
call all object finalize() methods.
\_ Does that actually FORCE garbage collection, or does
the system just treat it as a suggestion? Thanks.
\_ depends on the java VM. The ones I've worked with
actaully do a GC when you ask for one, but this
is not required by the language spec. - seidl
\_ Are you sure the problems are caused because the VM isn't
doing a gc? You could have objects which you think are dead,
but are still referenced and therefore not up for GC. You'll
need to use some tools to figure out.
Also, the VM you are using is important. Some Java VMs out there
use conservative gc, in fact I think all the Sun VMs before
HotSpot (which has an exact garbage collector) used conservative
gc. With conservative gc's, it's possible to have objects which
are collectable, but the garbage collector isn't *sure* they are
collectable, so to be safe it doesn't collect them (this can not
happen with an exact collector).
\_ Dude, if garbage collection is so complicated and delicate,
what the heck is the point? If I'm going to worry about
memory management with GC, why not just use new and delete?
New and delete are nice and simple and you don't have to
worry about all this weirdness; you just clean up after
after yourself.
\_ Implementation of GC is complicated and delicate, but
the use of a GC'd runtime system isn't. Or at least,
it shouldn't be -- the problem here is that the people
who originally designed an implemented Java are morons
(if you need any more proof, look at java.util.Date).
When using any reasonable garbage collector (like one
in any Smalltalk or the Java HotSpot), you just make new
objects and the garbage collector will reclaim when they
can no longer be used.
Now, you could make a programming error where something
you think should no longer be useable still is, but
if you have good programming habits, that shouldn't happen
very often. Far less often than memory leaks with malloc,
free.
\_ Also, if you set the variables' value to null I believe it will
be marked for garbage collection. Of course, this won't _force_
gc.
\_ This is a myth -- nulling vars does not help gc. Either
you need
the objects in those vars, in which case they should not be
up for gc and they should not be null (of course); or you
don't need them and you don't need the class holding on to
those variables, so the root class should be up for gc and
its ivars should be up for gc also.
I guess the above is not true if you have a class that is
long lived but puts objects that it only needs for a short
time into an variables, but that *probably* is a bad design.
\_ Perl has great GC mechanism, is easier to program (little error
\_ No. The way you wrote it, either meaning
was valid in English. See you at the end
of English 1A. Do not pass Go.
catching code required), is portable, and has BETTER GUI designer
(Perl/Tk). It is also OO (Perl5). GO PERL!
\_ Perl OO is about as intuitive as IRS tax
forms. It is incredibly awkward as well.
\_ Perl is easy for people with a unix
background. We're the target
audience. Sorry if that's not you.
What an insightful comment. Where did I say that I don't _/
have a unix background? I didn't? Then why did you make such an
inane statement? Look again: Perl is a great language for many
things, but it's impl of OO sucks.
\_ Thought you were talking about Perl as a whole, not Perl OO
in the second line.
\_ Please pay attention. Thank you for playing.
\_ No. The way you wrote it, either meaning was valid in
English. See you at the end of English 1A. Do not
pass Go.
\_ Bzzz! Try again. 'It' refers to 'Perl OO' not to
Perl.
\_ Duh. That was obviously your intended meaning
looking back with your able assistance to parse
your questionable grammar, but it is not the
only valid interpretation of what you said. You
are a dunce and a nincompoop. You're not quite
at the self-centered low-grade moron level but
keep trying and you'll make it soon enough.
\_ What part of "It...as well" doesn't
obviously refer to Perl OO.
\_ "It" can refer to either Perl or Perl OO
as used. Consult HS English teacher.
\_ "My car door is poorly implemented. It
is awkward to use as well." Do you
honestly mean that I could be talking
about the car or the car door? Moron.
\_ Geeks arguing about grammar arcana
are always so *cute* . . . I just
want to reach out and give the both
of you one great big *hug*!
\_ thread snipped. here you go:
alt.usage.english
\_ Perl GC doesn't catch circular structures because it uses
reference count GC.
\_ LISP! LISP! LISP IS THE STANDARD! Garbage collection language.
\_ PERL IS THE BEST, JAVA SUCKS!!!!! -sys adm
\_ JAVA IS THE BEST, PERL SUCKS!!!!! -god
\_ I don't think god reads the motd.
\_ *pshaw* Since when did you have to read the motd to
post to it? |
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