One of the nice news of Java 9 is the introduction of a REPL (Read-Eval-Print-Loop): JShell Let’s take a look at how to use it.

Running JShell

If you have the latest version of the JDK installed just run /bin/jshell.

Running with Docker

If you don’t have Java 9 installed, you can run it using Docker:

docker run -it openjdk:9-jdk /bin/jshell Optionally, you can create an alias of this command in your ~/.bashrc, to avoid running it each time.

Useful commands

Taking a look at variables you declared:

/vars

Listing resources you typed:

/list

Opening a file:

/open filepath

and, very important, to exit:

/exit

For the entire list of available commands run: /help

For more info and live demo take a look at this good video by Miro Cupak @JavaOne conference.