Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Programming > Java > JVM Sizing

Reply
Thread Tools

JVM Sizing

 
 
Gilbert Ostlethwaite
Guest
Posts: n/a
 
      12-18-2006
Hi

Is there a maximum amount of memory that can be addressed by the JVM
and, if so, does it vary by JVM version?

Regards

 
Reply With Quote
 
 
 
 
Steve W. Jackson
Guest
Posts: n/a
 
      12-18-2006
In article <(E-Mail Removed). com>,
"Gilbert Ostlethwaite" <(E-Mail Removed)> wrote:

> Hi
>
> Is there a maximum amount of memory that can be addressed by the JVM
> and, if so, does it vary by JVM version?
>
> Regards


Yes, there is a maximum. It varies by platform, I know. As far as I'm
aware, it didn't change between 1.4.x and 1.5, and I don't think it has
for 1.6. But what it is depends on the underlying architecture.
--
Steve W. Jackson
Montgomery, Alabama
 
Reply With Quote
 
 
 
 
John Ersatznom
Guest
Posts: n/a
 
      12-18-2006
Gilbert Ostlethwaite wrote:
> Hi
>
> Is there a maximum amount of memory that can be addressed by the JVM
> and, if so, does it vary by JVM version?


It varies with the -Xmx commandline parameter. E.g. -Xmx 256m gives it
256 megs (a quarter gig). Usually enough for anything.
 
Reply With Quote
 
Matt Humphrey
Guest
Posts: n/a
 
      12-19-2006

"John Ersatznom" <(E-Mail Removed)> wrote in message
news:em6ulp$ud7$(E-Mail Removed)...
> Gilbert Ostlethwaite wrote:
>> Hi
>>
>> Is there a maximum amount of memory that can be addressed by the JVM
>> and, if so, does it vary by JVM version?

>
> It varies with the -Xmx commandline parameter. E.g. -Xmx 256m gives it 256
> megs (a quarter gig). Usually enough for anything.


Famous last words, like who could use more than 640K on a computer?

Matt Humphrey http://www.velocityreviews.com/forums/(E-Mail Removed) http://www.iviz.com/


 
Reply With Quote
 
John Ersatznom
Guest
Posts: n/a
 
      12-19-2006
Matt Humphrey wrote:
> "John Ersatznom" <(E-Mail Removed)> wrote in message
> news:em6ulp$ud7$(E-Mail Removed)...
>
>>Gilbert Ostlethwaite wrote:
>>
>>>Hi
>>>
>>>Is there a maximum amount of memory that can be addressed by the JVM
>>>and, if so, does it vary by JVM version?

>>
>>It varies with the -Xmx commandline parameter. E.g. -Xmx 256m gives it 256
>>megs (a quarter gig). Usually enough for anything.

>
>
> Famous last words, like who could use more than 640K on a computer?


I'm not claiming it's "all you'll ever need", just that it's usually
enough for *current* stuff.
 
Reply With Quote
 
Gilbert Ostlethwaite
Guest
Posts: n/a
 
      12-19-2006
>
> Yes, there is a maximum. It varies by platform, I know. As far as I'm
> aware, it didn't change between 1.4.x and 1.5, and I don't think it has
> for 1.6. But what it is depends on the underlying architecture.
>


Do you know where this might be documented - I've not been able to find
anything to date.

Regards

 
Reply With Quote
 
Steve W. Jackson
Guest
Posts: n/a
 
      12-19-2006
In article <(E-Mail Removed) .com>,
"Gilbert Ostlethwaite" <(E-Mail Removed)> wrote:

> >
> > Yes, there is a maximum. It varies by platform, I know. As far as I'm
> > aware, it didn't change between 1.4.x and 1.5, and I don't think it has
> > for 1.6. But what it is depends on the underlying architecture.
> >

>
> Do you know where this might be documented - I've not been able to find
> anything to date.
>
> Regards


First, let me qualify this by saying that I'm talking about the largest
value that can be used with the -Xmx switch. Other respondents mention
the JVM's default maximum heap size, which is not what I thought the
original query wanted.

I haven't seen any written documentation on the allowable values for
this setting, but I have experimented with it because of questions and
issues I've dealt with. So I know, for instance, that the Java mailing
list for Mac developers has discussed it and concluded that the largest
setting is 2108m. I don't recall the largest value in a Linux setting,
but I've experimented on Windows XP and found that it's 1612m. I
learned this using the command "java -Xmx####m" and playing a sort of
high-low game until I got the maximum value.

= Steve =
--
Steve W. Jackson
Montgomery, Alabama
 
Reply With Quote
 
Tris Orendorff
Guest
Posts: n/a
 
      12-21-2006
"Gilbert Ostlethwaite" <(E-Mail Removed)> burped up warm pablum

in news:(E-Mail Removed) ups.com:

> Hi
>
> Is there a maximum amount of memory that can be addressed by the JVM
> and, if so, does it vary by JVM version?
>
> Regards
>


Well, a 32 bit JVM could address up to 4 GB of memory. A 64 bit JVM could
address up to 2^34 GB of memory.

--
Tris Orendorff
[Q: What kind of modem did Jimi Hendrix use?
A: A purple Hayes.]


 
Reply With Quote
 
Tim Slattery
Guest
Posts: n/a
 
      12-21-2006
Tris Orendorff <(E-Mail Removed)> wrote:

>"Gilbert Ostlethwaite" <(E-Mail Removed)> burped up warm pablum
>
>in news:(E-Mail Removed) ups.com:
>
>> Hi
>>
>> Is there a maximum amount of memory that can be addressed by the JVM
>> and, if so, does it vary by JVM version?
>>
>> Regards
>>

>
>Well, a 32 bit JVM could address up to 4 GB of memory. A 64 bit JVM could
>address up to 2^34 GB of memory.


Why 2**34, that's only two bits more address space than the 4GB 32-bit
version?

--
Tim Slattery
(E-Mail Removed)
http://members.cox.net/slatteryt
 
Reply With Quote
 
Lew
Guest
Posts: n/a
 
      12-22-2006
Tris Orendorff <(E-Mail Removed)> wrote:
>> Well, a 32 bit JVM could address up to 4 GB of memory. A 64 bit JVM could
>> address up to 2^34 GB of memory.


Tim Slattery wrote:
> Why 2**34, that's only two bits more address space than the 4GB 32-bit
> version?


2^34 is substantially larger than 4. Both were in units of GB.

- Lew
 
Reply With Quote
 
 
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Mozilla 1.7.6 image sizing Cueless Firefox 5 04-07-2005 11:01 PM
TEXT SIZING buttons Jeff Firefox 0 09-18-2004 05:10 PM
MS JVM and Sun JVM problem Young-Jin Lee Java 3 01-21-2004 04:25 AM
Different behavior for newStringUTF() for Sun JVM and IBM Jvm Lasse Java 1 01-05-2004 07:49 PM
Re: Handling both MS JVM and Sun JVM Kevin Hooke Java 2 09-02-2003 05:31 AM



Advertisments