Open Treet.java in JShell

Hello! I have a very basic question about JShell. In the video, Craig used Java REPL, which I assume does about the same thing as JShell does. I tried to follow along in JShell, since that's the REPL I've got used to and have been using since I started learning Java. However, I couldn't quite figure out how to open Treet.java. I tried "/open com/teamtreehouse/Treet.java", which I figured would be the most reasonable command. But it gives me this error message:

Error: 
Illegal start of expression 
package com.teamtreehouse;
^

After a few google searches, I understand that the command I used to open the file supposedly should work, so now I need help figuring out what mistakes I've made and what is the correct way to open a file in a package.

Thanks in advance!