[arch-general] Package guidelines for apps requiring a specific Java version

[Guillaume ALAUX]

On 2 October 2014 18:41, Maxwell Anselm <silverhammermba at gmail.com> wrote:
> I'm working on a PKGBUILD for a Java app that must be built and run using
> Java 8, but I couldn't find any guidelines on best practices for such a
> situation.
>
> The easy part is including 'java-environment=8' and 'java-runtime=8' in
> makedepends and depends respectively, but how to ensure the right version
> is set as default when building and running (rather than spitting out the
> opaque Java errors you get when using the wrong version)?
>
> Right now at the start of build() I have
>
> echo "Checking that default Java is version 8..."
>
> java -version 2>&1 | grep 'version "1.8'
>
>
> Which seems reasonable since building is infrequent. But what about for the
> shell script that starts the app? I could put a similar check there, but
> that seems like it would be really annoying for people who have multiple
> Java versions installed. Could there be a good way of letting my app always
> use Java 8, even if some other version is set as the default?
>
> Thanks,
> Max

Hello,

> The easy part is including 'java-environment=8' and 'java-runtime=8' in
> makedepends and depends respectively
Yes. Also note existence of "java-runtime-headless" in case your
application does not require graphical stuff (if it does not have a
GUI).

> how to ensure the right version is set as default when building
If building in a chroot (using scripts in package "devtools") and as
you added a makedependency on "java-environment=8" then jdk8-opendjk
and its dependencies will be the only ones installed. Thus your
application will automatically be built with it.

If building on a box where multiple JVM can be installed: build
scripts for Java apps usually provide a "--with-jdk=<PATH>" or
"--java-home=<PATH>" (or similar) to force the JVM to use to build. If
true for the app you are trying to build then you could use path
"/usr/lib/jvm/java-8-openjdk/"

Same applies when running the application: it usually involves a
script that checks where the JVM is located that usually takes the
same kind of parameter to "force" the JVM.

What is the name/URL of this app?