ADDITIONAL SYSTEM INFORMATION :
openjdk version "12-ea" 2019-03-19
OpenJDK Runtime Environment 19.3 (build 12-ea+10)
OpenJDK 64-Bit Server VM 19.3 (build 12-ea+10, mixed mode)


A DESCRIPTION OF THE PROBLEM :
After using an external editor, only the first snippet is taken into account by JShell. For demonstration purposes I used Notepad, but the same issue exists with Visual Studio Code.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
* run JShell and run the following 2 commands:
/set editor notepad.exe
/edit
* in the Notepad window, enter 2 variable declarations:
var i = 1;
var j = 2;
* save the file in Notepad and close the Notepad window
* in JShell, list the variables:
/vars

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
| int i = 1
| int j = 2
ACTUAL -
| int i = 1

CUSTOMER SUBMITTED WORKAROUND :
Use the built-in default editor