[fedora-java] /usr/lib/jni support in Fedora

[Christopher]

On Tue, Jul 29, 2014 at 7:05 AM, Florian Weimer <fweimer at redhat.com> wrote:

> As far as I can tell, currently, System.loadLibrary() is mostly unusable
> for Java libraries because they cannot influence the library search path.
>  If you want to transparently load a DSO, you need to use System.load() and
> hard-code the path.  This probably means patching upstream sources.
>
> To be clear, you can use LD_LIBRARY_PATH, or -Djava.library.path to
influence the search path in any launch scripts, just like you'd control
the bootstrap classpath in those same scripts. By choosing to use
System.loadLibrary(), instead of System.load(), the developer has already
decided to defer any influence over the search path to something external,
like a script (or the system's ld cache), so I've not found this to be much
of a limitation. I'm sure there are arguments against doing this, but it is
imprecise to say that it's not possible.


> Debian patches the default search path so that System.loadLibrary()
> searches /usr/lib/jni for DSOs with native code.  This means that classes
> which call System.loadLibrary() just work, assuming that the Debian package
> installs its DSOs into /usr/lib/jni.
>
> Forgive my ignorance, but what exactly is wrong with just using
/usr/lib[64], and how does putting them in a separate directory from other
system shared libraries offer any greater degree of control? It seems to me
that this solution is just as good as just putting the DSOs in
/usr/lib[64]. What am I missing? What's the difference?

Can we do something similar in Fedora?  We probably want /usr/lib/jni and
> /usr/lib64/jni, for consistency with the rest of the system.
>
> The upstream default search path starts with
> "/usr/java/packages/lib/amd64" (and variants for other architectures), but
> this isn't mentioned in the Fedora guidelines.  I'm also not sure if we
> want to use this file system location because it doesn't look particularly
> FHS-compliant.  But the proprietary JDKs could install a symlink there so
> that /usr/lib{,64}/jni is searched as well.
>
> --
> Florian Weimer / Red Hat Product Security
> --
> java-devel mailing list
> java-devel at lists.fedoraproject.org
> https://admin.fedoraproject.org/mailman/listinfo/java-devel
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