How to install jdtls?

[JRS-Developer]

Hello, I have tried to install jdtls using MasonInstall and it says that it's installed successfully but when I open a java file it shows up this message: "Client 1 quit with exit code 1 and signal 0"

I have already installed OpenJDK 17 using APT with Ubuntu 16.04.

I tried executing jdtls from ~/.local/share/nvim/mason/bin and it shows up this message:

Traceback (most recent call last):
File "./jdtls", line 17, in
jdtls.main(sys.argv[1:])
File "/home/jose/.local/share/nvim/mason/packages/jdtls/bin/jdtls.py", line 68, in main
parser.add_argument("--validate-java-version", default=True, action=argparse.BooleanOptionalAction)
AttributeError: module 'argparse' has no attribute 'BooleanOptionalAction'

[williamboman]

Hello! So the jdtls executable requires python3 to be installed (which python3 should produce a path). Not only that, they require Python >= 3.9 to be installed. It's a bit unfortunate if you ask me because it hurts portability, but it is what it is. What Python version do you have installed (python3 --version)?

[smjonas]

For anyone else reading this, be careful! Don't blindly upgrade your Python version on Linux. I followed this tutorial to upgrade to 3.9. However, this broke many things on my machine, including the update manager. I had to revert it. Not sure if there is a way to upgrade such that jdtls points to a different python version than the one that python3 --version returns. As of now, this requirement prevents me from using jdtls...

[mikehaertl]

@smjonas You could try pyenv. It allows you to

• have multiple versions of python installed in parallel
• select the python version to use on your user shell
• select the python version to use on the system level (change not recommended!)
• select the python version to use for a specific project/directory (requires pyenv-virtualenv plugin)

While the docs may look intimidating the setup is actually quite easy and only requires some lines in your .bashrc and .profile (plus installation of some OS dependent build tools to install other python versions).

Disclaimer: I'm not a python expert and also did not try if this fixes the problem as my system already uses python 3.10 as default. But it's worth a try.