An enviornment variable to reference an external build of JDT-LS

[mickaelistria]

Discussed in #3149

^{Originally posted by mickaelistria June 12, 2023}
Hi,
I'm trying to test changes in upstream JDT or m2e down to VSCode-Java. As I have JDT-LS code locally and am comfortable playing with it, I can produce a JDT-LS build with the desired content.
Now I'm looking for a way to get VSCode-Java using this local build without having to build/install a local extensions and without tweaking the default deployment (I'd like to avoid playing with the internal filesystem of the extension to replace the server/ folder with alternative content or a symlink, so I keep easy access to default behavior by default). Ideally, I would hope for an environment variable I can set to reference an alternative location for JDT-LS and would use it when starting VSCode for testing purpose.
I couldn't find anything allowing to easily achieve that in the code; but I'm not much fluent with the codebase, so maybe I missed something... Did I miss something? If not, I will open an issue to suggest such a env variable for easier testing.

[mickaelistria]

Submitted PR to achieve that: #3152