why 32 bit ubuntu can install 64 bit openjdk?

[mcheung63]

hi all

why 32 bit ubuntu can install 64 bit openjdk?

/root>uname -a
Linux peter-ubuntu 3.8.0-19-generic #30-Ubuntu SMP Wed May 1 16:35:23 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
/root>java -version
java version "1.7.0_21"
OpenJDK Runtime Environment (IcedTea 2.3.9) (7u21-2.3.9-1ubuntu1)
OpenJDK 64-Bit Server VM (build 23.7-b01, mixed mode)

thanks
from Peter ([email protected])

 

[Sven Köhler]

hi all

why 32 bit ubuntu can install 64 bit openjdk?

/root>uname -a
Linux peter-ubuntu 3.8.0-19-generic #30-Ubuntu SMP Wed May 1 16:35:23 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

I see a 64Bit kernel. Note the x86_64.

So probably you have ubuntu 64 bit? ;-)


Regards,
Sven

 

[Silvio]

hi all

why 32 bit ubuntu can install 64 bit openjdk?

/root>uname -a
Linux peter-ubuntu 3.8.0-19-generic #30-Ubuntu SMP Wed May 1 16:35:23 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
/root>java -version
java version "1.7.0_21"
OpenJDK Runtime Environment (IcedTea 2.3.9) (7u21-2.3.9-1ubuntu1)
OpenJDK 64-Bit Server VM (build 23.7-b01, mixed mode)

thanks
from Peter ([email protected])

Ubuntu is a Java application. Once you installed 64 bit Java your Ubuntu
system became 64 bit as well...

 

[Silvio]

You're kidding right?

Is it April 1st

lipska

Of course I am. The OPs system information states its 64-bitness three
times so I was just indirectly telling him to look a bit harder.

 

[Roedy Green]

Of course I am. The OPs system information states its 64-bitness three
times so I was just indirectly telling him to look a bit harder.

I would think it plausible an OS installer would automatically choose
64 bit if there is 4+ MB of RAM. What should he type to find out what
he has?

 

[Sven Köhler]

I would think it plausible an OS installer would automatically choose
64 bit if there is 4+ MB of RAM. What should he type to find out what
he has?

He already typed "uname -a" which gave him all the information he could
wish for in this case. In particular, the output told him that his
kernel was a 64bit kernel.

It is possible to run odd combinations of a 64Bit kernel and a 32 Bit
userland. However, to the best of my knowledge Ubuntu doesn't support
that. Hence, we should assume that he runs 64Bit userland. Hence,
apt-get installed the 64bit openjdk.


Regards,
Sven

 

[Arne Vajhøj]

I would think it plausible an OS installer would automatically choose
64 bit if there is 4+ MB of RAM.

That would be very stupid.

As a 64 bit Java would not run on a 32 bit OS with more than 4 GB of
memory.

What should he type to find out what
he has?

That was actually part of OP's post!

Arne

 

[Jukka Lahtinen]

On 7/2/2013 3:25 PM, Roedy Green wrote:

That would be very stupid.
As a 64 bit Java would not run on a 32 bit OS with more than 4 GB of
memory.

There wouldn't BE a 32 bit OS with more than 4 GB of memory, if the OS
installer would automatically choose a 64 bit version.

 

[Sven Köhler]

There wouldn't BE a 32 bit OS with more than 4 GB of memory, if the OS
installer would automatically choose a 64 bit version.

Arne understood the comment of Roedy differently: he thinks that Roedy
meant package manager when saying "OS installer". In result, Arne
thought was thinking that Roedy was suggesting that the package manager
should install 64Bit Java if RAM > 4GB.

 

[Arne Vajhøj]

There wouldn't BE a 32 bit OS with more than 4 GB of memory, if the OS
installer would automatically choose a 64 bit version.

Roedy's wording is a bit "fuzzy".

But given the topic of the thread "why a 64 bit JDK can be installed
on 32 bit OS" then I assumed that it was about installing Java not
about installing Linux.

Furthermore I believe with Ubuntu you explicit pick 32 or 64
bit version to install.

But given the post Roedy did reply to then it could be Linux
he meant.

Arne

 

[Joerg Meier]

Of course there could. If you want that, you just run a Linux PAE kernel
on 64 bit hardware.

How would you run a PAE kernel if a 64 bit kernel was automatically
installed ? While what you said is true, you don't seem to have read what
you responded to.

Liebe Gruesse,
Joerg

 

[Jukka Lahtinen]

Huh? IIRC it is the JRE that's being automatically installed, not the
kernel. If the installer is any good, it should recognise that its

The OS installer installs the OS, and if it has chosen a 64-bit version,
there will be no PAE kernel installed.
OTOH, you often choose the OS version (including bitness) by choosing
a specific installation media, and that is done before starting
the installer.