Re: [Wrapper-user] Detecting JVM version (32 bit vs. 64 bit) (was Re: getting hardware arch using just java)

[David F. <dav...@zi...>]

I think I found the answer to my question regarding detection of  
64bit JVM. If anyone has a better solution, do tell.

Seems Sun has a Java System property to determine the bitness of the  
JVM: 32 or 64:

sun.arch.data.model=32   // 32 bit JVM
sun.arch.data.model=64  // 64 bit JVM

As with any proprietary System property, it may only work on Sun's  
JVM (ie: not IBM's). It may disappear in the future...

Regards,
David

On Jun 7, 2006, at 12:15 PM, David Ferrero wrote:

> Thanks Leif, but I think I wasn't clear enough in my first post.
>
> I am trying to build one installer that takes care of all java  
> supported OS / JVM possibilities. I have reviewed the testwrapper  
> shell script in the JWS bin directory. As I understand it, it works  
> as follows:
>
> By default it will use the 32 bit version of the wrapper binary. If  
> it can't find that, it will test for the 64 bit version (or in the  
> case of Mac OS X, the universal binary) and run that instead. If it  
> can't find either, it will display an error message.
>
> Please correct me if I'm wrong, but it would appear that it is my  
> software installer's responsibility to detect if the user is  
> installing on a  64-bit JVM. If both the 32 bit and 64 bit wrapper  
> binaries were present, that it would attempt to use the 32 bit  
> wrapper binary first and it would fail on a 64 bit JVM environment.
>
> Is there any way to detect if they are using a 64-bit JVM? I would  
> like to avoid having to display an error and requiring the user to  
> delete the 32-bit wrapper binary manually before restarting.  Is  
> the best we can do to document the 64-bit JVM situation?
>
> Thanks for any clarity anyone can share about detecting 64-bit JVM  
> or the inner workings of JWS that I may be mistaken about.
>
>
>
>> From: Leif Mortenson <leif@ta...>
>>
>> <msg.gif>
>>  Re: getting hardware arch using just java
>> 2006-06-07 00:54
>>  David,
>>      The files in the delta pack can be deleted as you wish, or even
>>  added if you have
>>  compiled the wrapper for other platforms.   In general, the
>>  wrapper-xx-xx-64 files
>>  are not really needed as the 32 bit versions work fine on the 64 bit
>>  platforms.
>>  The libwrapper-xx-xx-64.so files are required if a 64 bit JVM is  
>> being
>>  used.  The
>>  32.so files are used by 32 bit JVMs regardless of whether the  
>> hardware
>>  is 32 or
>>  64 bits.
>>
>>  Cheers,
>>  Leif
>>
>>  David Ferrero wrote:
>>  > If I want the wrapper scripts to detect the proper architecture
>>  > native libs to use, and I want to minimize the installation  
>> size of
>>  > my software, can I have my installer script install just the OS  
>> bits
>>  > for a given OS instead of the whole delta-pack?
>>  >
>>  > ie:
>>  >
>>  > For os.name="Linux", could I have my Installer just copy the Linux
>>  > scripts plus the following files?
>>  > lib/wrapper.jar
>>  > lib/libwrapper-linux-ppc-64.so
>>  > lib/libwrapper-linux-x86-32.so
>>  > lib/libwrapper-linux-x86-64.so
>>  >
>>  > Thanks for clarifying,
>>  >
>>  > David
>>  >
>
>