jpackage: support for environment variables in --java-options

[Michael Hall]

> On Sep 2, 2020, at 9:04 AM, Andy Herrick <andy.herrick at oracle.com> wrote:
> 
> Yes - environment variables are not a good answer for this, not just mac, but even on windows the env variables at run time are different if launched from a shell (the env variables of that shell) vs. when run from a shortcut (the system-wide or user env variables set in Control Panel or Settings dialog).
> 
> JEP-343 says jpackage should be "a tool for packaging self-contained Java applications.", so an app packaged with jpackage should run on a machine without requiring any other files to be installed .  That should not prohibit optional configuration from being discovered on a machine and used to tune the application or it's use of Java.
> 
> Normally, any such discovery can be done by the application itself, except where it is the the java options that tune the java vm itself, and that is why we are considering mechanisms (such as expanding environment variables at runtime, or reading an installed configuration file of some kind)
> 
It’s difficult and was difficult with java applications on OS X from the start to have an application support anything like command line invoking with parameters.

Maybe add standalone options for the command that update an existing application bundle? Of course then there would probably be signing and other issues.

Again, for LSEnvironment on OS X I think it wouldn’t be terribly difficult to implement. You could handle it something like it appears file associations work. Although, I haven’t done anything with those yet. Then just modify the Info.plist. I have had code that does that in the past. XML right?

In the past I have had need to add environment variables to my application to interface it with the R language. Also  debugging AppleScript related at one point required environment variables. It was very much an OS X only java app at one point in time.
Recently I had problems interfacing to Anaconda python that it seemed like being able to set the PATH variable might resolve. Although my own attempts to set the variables to get it to work failed. What did work was command line shell invoking the application. Like myApp.app/Contents/MacOS/myApp from Terminal. That was for someone else’s application.
I decided just to set a alias for that in .bash_profile for my own use and not try to figure what exactly the Finder launched application needed to make it work.
So these are some use cases where environment variables were involved. A feature to support them could occasionally be nice.