The Problem

I tried to run a simple java code segment in my note book but it gave me this error

Failed to start the Kernel. 

Kernel Java is not usable

The Solution

Disclaimer: There is definitely a more convenient way to do this, and since I am not an expert I realize that I have like zero idea what I’m talking about

Step 1: Uninstall basically everything on your computer

pip3 uninstall jupyter
pip3 uninstall jupyter_core
pip3 uninstall jupyter-client
pip3 uninstall jupyter-console
pip3 uninstall notebook
pip3 uninstall qtconsole
pip3 uninstall nbconvert
pip3 uninstall nbformat

pip uninstall ipykernel
pip uninstall jupyterlab-server
pip uninstall jupyterlab

I got these commands from a very nice lady on GitHub Link

Step 2: Start reinstalling things

I have no idea what those lines deleted but just I just followed Mr. M’s commands to reinstall things that I probably already had installed but I just wanted to make sure

$ brew list # list packages
$ brew update # update package list
$ brew upgrade # upgrade packages
$ brew install git  # install latest git
$ brew install python # install python3 for development
$ python --version # version of python3 installed
$ brew install java # openjdk install
$ java --version # version of runtime
$ javac --version # version of compiler

(base) id:~$ conda --version 
(base) id:~$ conda install jupyter # install jupyter
(base) id:~$ jupyter kernelspec list # list installed kernels

(base) id:~$ # start in home directory
(base) id:~$ pip install bash_kernel # download bash kernel

This is when I realized that there might be something wrong with my bash because it gave me a weird response, and this is where I discovered that it was in fact broken

Step 3: Fix Bash

pip uninstall bash_kernel
pip install bash_kernel

It then give me a list of conflicts because the things we needed installed were uninstalled

Type this commands into terminal:

conda install -c conda-forge rtree

For more information click: Link

Then, uninstall and reinstall bash again

pip uninstall bash_kernel
pip install bash_kernel

And it fixed it somehow

Important note!

Don’t forget to reinstall things such as nbformat, or anything not covered by the conda-forge rtree line! It will cause issues later with Jupyter notebooks