java - How exactly to set up and use environment variables on mac

Question

What is the proper (2021 way) of creating a permanent environment variable on a mac (Big Sur), and then use it within a java project.

There are many very old posts regarding this topic. none of them seem to work properly nowadays.

1. How to add a permanent environment value (through terminal)
2. And how can I use it in a java code

(I'm also not sure how I was able to add my testvar=testvalue to the list because I tried so many files [although it seems none of them worked], by adding "export testvar=testvalue" to the following files:

• /etc/paths
• ~/.bashrc
• ~/.bash_profile
• ~/.profile
• /etc/profile

Also after inserting it into each file I used source {file}

So at this point I have no idea which is the proper way to create and have it permanently, and being able to use it in my java code)

So far, I can print the variables into the terminal with

printenv

My variables are getting listed, example:

testvar=testvalue

In my java code, I get null when using:

System.getenv("testvar")

however using an other variable name -that was not created by me, but the macos system- (eg. "USER" ) prints the value as expected.

Answer 1

等待大神答复