How to run JShell on Mac OS X when Java 8 and Java 9 are installed

TIL how to run JShell on Mac OS X when both Java 8 and Java 9 are installed.

In short: what is JShell?

JShell is one of the new features in Java 9. It is a REPL (Read Evaluate Print Loop) for Java, which evaluates declarations, statements, and expressions as they are entered and immediately shows the results.

Let's run it!

I currently have both Java 8 and Java 9 installed on my Mac. Note that my JAVA_HOME points to Java 8.

$ java -version
$ java version "1.8.0_121"
$ Java(TM) SE Runtime Environment (build 1.8.0_121-b13)
$ Java HotSpot(TM) 64-Bit Server VM (build 25.121-b13, mixed mode)

Let's try to run JShell:

$ jshell
$ Unable to locate an executable at "/Library/Java/JavaVirtualMachines/jdk1.8.0_121.jdk/Contents/Home/bin/jshell" (-1)

Hmm. In order to run JShell we must go to the place where the JShell executable is located:

$ cd /Library/Java/JavaVirtualMachines/jdk-9.0.1.jdk/Contents/Home/bin/

Now we can run JShell, hooray! 🎉

$ ./jshell 
|  Welcome to JShell -- Version 9.0.1
|  For an introduction type: /help intro

jshell> 

Have fun experimenting.


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