How to create scratch variables in JShell in Java 9?

JavaObject Oriented ProgrammingProgramming

JShell is a REPL interactive tool introduced in Java 9 to execute and evaluate simple java programs like variable declarations, statements, expressions, and the programs without using the main() method.

In JShell, any value returned by a snippet automatically saved into a scratch variable. These scratch variables can be represented by $. When we do not assign the result of an expression to a variable, a scratch variable is created in JShell so that an output of expression can be used later.

In the below code snippet, six scratch variables have created

C:\Users\User>jshell
| Welcome to JShell -- Version 9.0.4
| For an introduction type: /help intro

jshell> 3+7
$1 ==> 10

jshell> 9-2
$2 ==> 7

jshell> 4*4
$3 ==> 16

jshell> 12/4
$4 ==> 3

jshell> 19%5
$5 ==> 4

jshell> String.valueOf($2)
$6 ==> "7"


In the below code snippet, the "nonScratch" variable has created. It is not a scratch variable because it can't be represented with $.

jshell> String nonScratch = "Tutorialspoint"
nonScratch ==> "Tutorialspoint"

jshell> 


In the below code snippet, "/vars" command can display both scratch and non-scratch variables for that particular session.

jshell> /vars
|    int $1 = 10
|    int $2 = 7
|    int $3 = 16
|    int $4 = 3
|    int $5 = 4
|    String $6 = "7"
|    String name = "Tutorialspoint"

jshell>
raja
Published on 27-Feb-2020 11:34:57
Advertisements