How to set a specific version of Java as JAVA_HOME in Fish in macOS

Question

I was using Bash as my default shell on macOS but I decided to switch to Fish.

I am trying to switch between different versions of Java. In bash it was done using the ~/.bash_profile

export JAVA_HOME=`/usr/libexec/java_home -v 1.7`

I have set the equivalent on Fish ~/.config/fish/fish_variables

set -x JAVA_HOME `/usr/libexec/java_home -v 1.7`

Unfortunately, Java version is not being changed. How can I set environment variables (specific version of Java, in particular) using ~/.config/fish/fish_variables?

UPDATE:

According to the FAQ, instead of ~/.config/fish/fish_variables, ~/.config/fish/config.fish should be used. Also I created ~/.config/fish/fish.config instead of ~/.config/fish/config.fish.

Answer 1

While I am not deeply familiar with Fish, based on what I am reading it seems like the issue is with the backticks in your command:

/usr/libexec/java_home -v 1.7

You see that is just like this in Bash:

$(/usr/libexec/java_home -v 1.7)

Keep that in mind and look at this Fish FAQ entry:

How do I run a subcommand? The backtick doesn't work!

fish uses parentheses for subcommands. For example:

for i in (ls)
    echo $i
end

Knowing that the config line should most likely be:

set -x JAVA_HOME (/usr/libexec/java_home -v 1.7)

Answer 2

function javaenv
   if test (count $argv) -eq 0
       /usr/libexec/java_home -V
   else
       switch $argv[1]
       case 'ls'
           /usr/libexec/java_home -V
       case 'set'
           set -xU JAVA_HOME (/usr/libexec/java_home -v $argv[2])
       end
   end
end

Can put the function above in ~/.config/fish/functions and use it to get the java_home contents with

javaenv

and set the contents of java_home with

javaenv set 1.8

Idea and contents taken from here