Is Java 9 better than other versions of Java?

Hi people! I'm taking a programming course in a company, and our mentor just told us to install Java 9 cause other version of Java don't have the Jre. I'm sick, so this is what a friend told me.. I couldn't ask this to my mentor personally, so, is that true? Searching on the internet I read that further versions of the jdk have Jre but launch only one internal enviroment, while jdk9 launches 2 instances of the jre. Now, the latest version is 12,is that the version I should use or have to Install java9 cause there could be some differences with java9(talking about the course I'm taking, for using the same version with everyone).

Also our mentor told us to implement 3 different environment variable while on internet I only see others suggest to implement this : Path. C/progfiles/java/jdk*/bin

My mentor told us to implement more,those 2: Classpath. C/progfiles/java/jdk Jre_home. C/profiles/java/jre*

Is it necessary to install those 2?

 

my issue has been solved!