Java 9 : JShell

 1. How to run Jshell

    get a command prompt windows key + R --> type cmd

2. Check java version, should be higher than 9

    java -version

3. type "jshell"

4. Now you can write syntax and check validity , edit and play on with this

5. /help --> help command

6. /list   --> will list the command typed/executed

7. edit use edit command with command number, number you can select using /list . Once you use edit, it will prompt with shell to edit.

    /edit 2

Below you I have attached series of commands i tried with all mistakes

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Microsoft Windows [Version 10.0.22621.2715]

(c) Microsoft Corporation. All rights reserved.

C:\Users\USR>java -version

openjdk version "21" 2023-09-19

OpenJDK Runtime Environment Zulu21.28+85-CA (build 21+35)

OpenJDK 64-Bit Server VM Zulu21.28+85-CA (build 21+35, mixed mode, sharing)

C:\Users\USR>jshell

|  Welcome to JShell -- Version 21

|  For an introduction type: /help intro

jshell> System.out.println("Hello");

Hello

jshell> /help

|  Type a Java language expression, statement, or declaration.

|  Or type one of the following commands:

|  /list [<name or id>|-all|-start]

|       list the source you have typed

|  /edit <name or id>

|       edit a source entry

|  /drop <name or id>

|       delete a source entry

|  /save [-all|-history|-start] <file>

|       Save snippet source to a file

|  /open <file>

|       open a file as source input

|  /vars [<name or id>|-all|-start]

|       list the declared variables and their values

|  /methods [<name or id>|-all|-start]

|       list the declared methods and their signatures

|  /types [<name or id>|-all|-start]

|       list the type declarations

|  /imports

|       list the imported items

|  /exit [<integer-expression-snippet>]

|       exit the jshell tool

|  /env [-class-path <path>] [-module-path <path>] [-add-modules <modules>] ...

|       view or change the evaluation context

|  /reset [-class-path <path>] [-module-path <path>] [-add-modules <modules>]...

|       reset the jshell tool

|  /reload [-restore] [-quiet] [-class-path <path>] [-module-path <path>]...

|       reset and replay relevant history -- current or previous (-restore)

|  /history [-all]

|       history of what you have typed

|  /help [<command>|<subject>]

|       get information about using the jshell tool

|  /set editor|start|feedback|mode|prompt|truncation|format ...

|       set configuration information

|  /? [<command>|<subject>]

|       get information about using the jshell tool

|  /!

|       rerun last snippet -- see /help rerun

|  /<id>

|       rerun snippets by ID or ID range -- see /help rerun

|  /-<n>

|       rerun n-th previous snippet -- see /help rerun

|

|  For more information type '/help' followed by the name of a

|  command or a subject.

|  For example '/help /list' or '/help intro'.

|

|  Subjects:

|

|  intro

|       an introduction to the jshell tool

|  keys

|       a description of readline-like input editing

|  id

|       a description of snippet IDs and how use them

|  shortcuts

|       a description of keystrokes for snippet and command completion,

|       information access, and automatic code generation

|  context

|       a description of the evaluation context options for /env /reload and /reset

|  rerun

|       a description of ways to re-evaluate previously entered snippets

jshell>

/list

   1 : System.out.println("Hello");

jshell> void printMessage(){

   ...>     System.out.print;n("Hello")

   ...> }

|  Error:

|  not a statement

|      System.out.print;n("Hello")

|      ^--------------^

|  Error:

|  ';' expected

|      System.out.print;n("Hello")

|                                 ^

jshell> printMessage()

|  Error:

|  cannot find symbol

|    symbol:   method printMessage()

|  printMessage()

|  ^----------^

jshell> /lsit

|  Invalid command: /lsit

|  Type /help for help.

jshell> /list

   1 : System.out.println("Hello");

jshell>

        void printMessage(){

   ...>     System.out.print;n("Hello");

   ...> }

|  Error:

|  not a statement

|      System.out.print;n("Hello");

|      ^--------------^

|  Error:

|  cannot find symbol

|    symbol:   method n(java.lang.String)

|      System.out.print;n("Hello");

|                       ^

jshell> void printMessage(){

   ...>     System.out.println("Hello");

   ...> }

|  created method printMessage()

jshell> printMessage

|  Error:

|  cannot find symbol

|    symbol:   variable printMessage

|  printMessage

|  ^----------^

jshell> printMessage()

Hello

jshell> /list

   1 : System.out.println("Hello");

   2 : void printMessage(){

           System.out.println("Hello");

       }

   3 : printMessage()

jshell> edit 2

|  Error:

|  ';' expected

|  edit 2

|      ^

|  Error:

|  cannot find symbol

|    symbol:   variable edit

|  edit 2

|  ^--^

jshell> /edit 2

|  modified method printMessage()

jshell> printMessage()

Hello Edited

jshell>