mjhjmtu

I am new to bash. I have multiple java versions installed on my machine and I want to create an alias for all of them. Typically the executable for java is in folder /Library//bin/java. I want to create and alias so that I type java9 in bash and it executes executable for java9 (ad similarly for other java versions). How to do this.

Note typically for one javaversion I add JAVA_HOME and append the path in PATH. But not sure how to do this.

I was reading about this and looks like eval could be an option, but not sure how to do this.

javav () 
 local version="$1"
 shift

 case "$version" in
 8) JAVA_HOME='/Library/some/path/java' 
 PATH="$JAVA_HOME/bin:$PATH" java "$@"
 ;;
 8.7) JAVA_HOME='/Library/some/other/path/java' 
 PATH="$JAVA_HOME/bin:$PATH" java "$@"
 ;;
 9) JAVA_HOME='/Library/some/other/path2/java' 
 PATH="$JAVA_HOME/bin:$PATH" java "$@"
 ;;
 *) printf 'Unknown java version: %sn' "$version" >&2
 return 1
 esac

This is a shell function, javav (rename it if it clashes with any existing tool). You would put this in your .bash_profile or .bashrc file, or in its own file (in which case you would need to source it with source filename).

It takes a version number as its first argument and sets JAVA_HOME to the path of the appropriate directory, and PATH to include $JAVA_HOME/bin in the beginning before executing java with the remaining command line arguments. Since the java executable presumably lives in $JAVA_HOME/bin and since this is first in the PATH, that's the Java version that will be started.

This means that you use this like so:

$ javav 9 other arguments to java here

Assuming the function has been set up with the correct JAVA_HOME directory and PATH, this ought to launch Java 9 and pass other arguments to java here to the java executable.

Note: I'm not a Java developer, and I don't know if makes sense to set PATH the way I'm doing above, but you can modify it to fit your needs.