How to use different java version by alias?

Question

I have some tools that can only be run by java 8. So i downloaded java 8, but now i have two versions of java installed at the same time (os : Ubuntu):

java-1.11.0-openjdk-amd64      1101       /usr/lib/jvm/java-1.11.0-openjdk-amd64
java-1.8.0-openjdk-amd64       1081       /usr/lib/jvm/java-1.8.0-openjdk-amd64

My question is: is it possible to call these both versions by different aliases? For example i type:

• "java" to call java 11 (the default) and
• "java8" to call java 8

Answer 1

You could do it in a couple of ways. The easiest way would be to put the following 2 lines in your profile initialization file:

alias java='/usr/lib/jvm/java-1.11.0-openjdk-amd64/bin/java'
alias java8='/usr/lib/jvm/java-1.8.0-openjdk-amd64/bin/java'

Other ways are depending on whether you are the admin of the machine or not. You can create soft links like this: /usr/bin/java -> /usr/lib/jvm/java-1.11.0-openjdk-amd64 (Not recommended since certain tools in your system may depend on /usr/bin/java).

Update: Try to use sdkman if you can. Makes the job of installing java versions and setting up JAVA_HOME env variable simple.