jar file locations

[seddes]

Hi,
If an application uses "jar" files, where should they be placed? What is the convention?

Option 1) Create a directory under /usr/lib, and place them there. This is similar to how "mono" files/dll libs are to be handled. I see that there is a
/usr/lib/mozilla, /usr/lib/MozillaFirefox that comply with this.

Option 2) Create a directory under /usr/share/, and place them there. I see a /usr/share/gettext, /usr/share/largorecipes

Options 3) Put jar in /usr/lib, no subdir. I see a db-4.1.jar that does this.

Thanks for your help.

[roka]

If the app provides the jar files, they should be made avaliable under /usr/share/<appname>-<version>/lib
e.g. /usr/share/xerces-2/lib
Apps requiring a jar would ideally link to the lib from the providing package.

[seddes]

Ok, but with a mono app, per bug http://bugs.gentoo.org/show_bug.cgi?id=75192

this was the advice:

------- Additional Comments From latexer@gentoo.org 2004-12-21 10:12
PST -------
1) Use the mono eclass to avoid this MONO_SHARED_DIR problem.

2) As much as possible, *.exe should avoid going into /usr/bin. *.dll
*definitely* shouldn't be there. Please see how muine or blam handle the
placement of their files.

blam created a /usr/lib/blam, and put the dll's there. Seems like mono dlls and java jar files should be consistant....

To me, a jar and dll are similar, non-native libraries

[roka]

There seems to be different practices on installing shared libs between java and mono apps.

Here is an extract from the gentoo java policy

[latexer]

I've apparently been asked to weigh in on this.

Before i bother, people should read this which is a blog post by Todd Berman, one of the main authors of the monodevelop port of #develop. Second, I'll reference FHS spec found here in several places.

Really, the only discussion is about /usr/lib/ vs. /usr/share/:
The FHS states this:
/usr/lib/: /usr/lib includes object files, libraries, and internal binaries that are not intended to be executed directly by users or shell scripts.
/usr/share: The /usr/share hierarchy is for all read-only architecture independent data files.

With this in mind, jar files and dll files aren't *exactly* the same. In particular, *many* .NET libraries and executables use P/Invoke to call to C functions. See how muine uses libmuine.so to create a glue between .NET and native libraries. To my knowledge this happens a *lot* less frequently in Java.

That said, /usr/share/${subdir}/ makes tons of sense for compiled from source jar files (obviously /opt is optimal for non-compiled stuff). However, for .NET libraries that often times will have needed architecture *dependant* items, /usr/share is not the best. /usr/lib/${subdir}/ is better suited. Beyond that, often an app for simplicity sake will install the foo.exe in the same location, so that no extra work with env. vars is needed when executing to find the linked libraries (see muine or blam again for an example of this).

This does not break the requirement on /usr/lib/ not containing things executed by the user, as these exe files should be being called by a wrapper script in /usr/bin that uses mono to execute them.

Further complicating things is the use of the GAC (Global Assembly Cache), which is used by mono to store/retrieve/look-up assemblies. These get placed under /usr/lib/mono, and thereby adhere to the standard. Precompiled DLLs may also want to be registered in the GAC though, so this is a grey area (in my mind).

That's the best i can do right now, I'll write more later if people want me to expand on anything i said.
_________________
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[seddes]

Thanks for clearing that up. The idea of C# using glue/leveraging the existing libraries makes alot of sense to me.

[Ox-]

I put together an ebuild for myself of a project that is a server and some api libraries to connect to the server. One of the api's is java of course, so I had a heck of a time figuring out how to get the jar files installed (I'm not a java programmer so have almost no experience with it).

"ant install" tried to install the jar's in /usr/lib/java.

Another similar ebuild, the one for cyryus-sasl, put jar files into /usr/lib/java, but all the other ebuilds seemed to do the /usr/share/${PN}-${SLOT}/lib/ thing so I went that route.

Now one of these days I'll figure out how CLASSPATH gets set for all those zillions of /usr/share paths

[iulica]