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Re: Why dependency on both default-jre and java<N>-runtime

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On 23 August 2017 at 21:43, Thorsten Glaser <t.glaser@tarent.de> wrote:
> On Wed, 23 Aug 2017, Carnë Draug wrote:
>
>> However, java<N>-runtime packages are virtual packages provided by
>> default-jre so I don't understand why.  Could anyone clarify?
>
> They are also provided by openjdk-*-jre, so you can, for example,
> install a package depending on java6-runtime on wheezy (pre-LTS)
> whose default-jre pulled in openjdk-6-jre but run it with
> openjdk-7-jre instead of that. Or even openjdk-8-jre backported
> yourself.
>
> That’s extremely useful. It’s best to have at most *one* JRE
> on any given Debian system, after all. Experience speaking.
>
> bye,
> //mirabilos

Hi

Thank you for the answer but I still don't understand.  I get how the
use of virtual packages for java<N>-runtime allows one to choose
OpenJDK or Oracle JDK.  What I don't understand is the default-jre
*and* java<N>-runtime.  Actually, I don't understand the default-jre
at all if one also needs to specify a minimum java version via
java<N>-runtime.

Using your example, installing a package on wheezy that is dependent
on default-jre and java6-runtime allows one to use openjdk-7-jre
instead (I guess wheezy default-jre was once openjdk-6-jre).

However, being dependent on java6-runtime alone would suffice since
openjdk-7-jre would also provide it.  The extra dependency on
default-jre would only add openjdk-6-runtime which was not actually
necessary.

I'm probably missing something important on how the java alternatives
and jre's work.  I'm packaging a java program now (been doing some
work on the imagej package for debian-med), I would like to understand
this properly.

Thank you
Carnë

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Thread

Why dependency on both default-jre and java<N>-runtime Carnë Draug <carandraug+dev@gmail.com> - 2017-08-23 20:20 +0200
  Re: Why dependency on both default-jre and java<N>-runtime Thorsten Glaser <t.glaser@tarent.de> - 2017-08-23 22:50 +0200
    Re: Why dependency on both default-jre and java<N>-runtime Bas Couwenberg <sebastic@xs4all.nl> - 2017-08-24 16:20 +0200
      Re: Why dependency on both default-jre and java<N>-runtime Carnë Draug <carandraug+dev@gmail.com> - 2017-08-25 16:30 +0200
        Re: Why dependency on both default-jre and java<N>-runtime Thorsten Glaser <t.glaser@tarent.de> - 2017-08-25 16:40 +0200
          Re: Why dependency on both default-jre and java<N>-runtime Carnë Draug <carandraug+dev@gmail.com> - 2017-08-29 14:30 +0200
    Re: Why dependency on both default-jre and java<N>-runtime Carnë Draug <carandraug+dev@gmail.com> - 2017-08-24 16:20 +0200
  Re: Why dependency on both default-jre and java<N>-runtime Matthias Klose <doko@debian.org> - 2017-08-31 04:00 +0200

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