static.rainfocus.com...jshell> int age = 20 age ==> 20 jshell> age + 2 $2 ==> 22 jshell> 4 * $2 $3...

EAD

VAL

RINT

OOP

# conventional ceremony

public class HelloWorld {

public static void main(String[] args) {

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

}

}

# jshell

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

Hello World

$ jshell

| Welcome to JShell -- Version 9

| For an introduction type: /help intro

jshell> /help

jshell> /list 2 : age = 31 3 : int age = 29; 4 : int rate = 20;

jshell> /list age 3 : int age = 29;

jshell> /list 3 3 : int age = 29;

jshell> /list -a | -all s1 : import java.io.*; ...

s10 : import java.util.stream.*;

1 : int age = 30; 2 : age = 31 3 : int age = 29; e1 : rate = 20 4 : int rate = 20;


jshell> age + 2$2 ==> 22

jshell> 4 * $2$3 ==> 88

jshell> "JavaOne 2017"$4 ==> "JavaOne 2017"

jshell> /list 1 : int age = 20; 2 : age + 2 3 : 4 * $2 4 : "Java 9 hack day"jshell> /34 * $2$5 ==> 88jshell> $3$3 ==> 88

jshell> /help

jshell> /help edit

jshell> /help /types

jshell> /help /set format

jshell> /imports

jshell> /impor

jshell> /impo

jshell> /imp

jshell> /im

jshell> /i

jshell> /r| Command: '/r' is ambiguous: /reset, /reload| Type /help for help.

jshell> Math.random()$8 ==> 0.1891103887126322

jshell> /!Math.random()$9 ==> 0.5946399311904251

jshell> /!Math.random()$12 ==> 0.6901639842319651

3 jshell> int age = 20; age ==> 202 jshell> Math.random() $2 ==> 0.93330752174562061 jshell> age = 21 age ==> 21

jshell> /-2Math.random()$5 ==> 0.6042322785203164

jshell> int sum(int first, int second) { return first + second;}| created method sum(int,int)

jshell> int mean(int first, int second) { return sum(first, second) / 2; }| created method mean(int,int)

jshell> /m | /methods| int sum(int,int)| int mean(int,int)

jshell> /m sum| int sum(int,int)

jshell> int mean(int first, int second) { return (first + second) / 2; }| modified method mean(int,int)

jshell> abstract class Figure { abstract double area(); }| created class Figure

jshell> class Dog { String name; Dog(String name) {this.name=name;} }| created class Dog

jshell> public enum Day {SUNDAY, MONDAY, TUESDAY, WEDNESDAY, ...}| created enum Day

jshell> /t | /type| class Figure| enum Day| class Dog

jshell> /type Day| enum Day

jshell> /types| class Figure| enum Day| class Dog| class Rectagle

jshell> /drop Dog| dropped class Dog

jshell> /t| class Figure| enum Day

jshell> /list Figure 2 : abstract class Figure { abstract double area(); }

jshell> /drop 2| dropped class Figure

jshell> /drop 2| This command does not accept the snippet '2' : abstract class Figure { abstract double area(); }

jshell> /type| enum Day| class Rectangle| which cannot be referenced until class Figure isdeclared

jshell> class Employee { ...> private String name; ...> ...> Employee(String name) { ...> this.name = name; ...> } ...> ...> String name() { ...> return name; ...> } ...> ...> }

| created class Employee

jshell> new Employee("Joe")$2 ==> Employee@2f686d1f

jshell> $2. <tab>equals() getClass() hashCode() name() notifyAll() notify() toString() wait()

jshell> $2.name()$3 ==> "Joe"

jshell> /list 1 : class Employee { private String name; private String surname;

Employee(String name, String surname) { this.name = name; this.surname = surname; } String name() { return name; } String surname() { return surname; } } 2 : Employee joe = new Employee("Joe","Doe")

jshell> /save employeeSnippets

jshell> /exit| Goodbye

$ lsemployeeSnippets

jshell> /list Employee 1 : class Employee { private String name; private String surname;

Employee(String name, String surname) { this.name = name; this.surname = surname; } String name() { return name; } String surname() { return surname; } } 2 : Employee joe = new Employee("Joe","Doe")

$ lsemployeeSnippets

$ jshelljshell> /open employeeSnippets

jshell> joe.name()$5 ==> "Joe"

jshell> joe.surname()$6 ==> "Doe"

jshell> /env -class-path mongo-java-driver-3.4.2.jar

| Setting new options and restoring state.

jshell> /env

| --class-path mongo-java-driver-3.4.2.jar

jshell> import com.mongodb.MongoClient

jshell> MongoClient mongoClient = new MongoClient()

jshell> String context = "JavaOne 2017"

context ==> "JavaOne 2017"

| created variable context : String

jshell> /list

1 : String context = "JavaOne 2017";

jshell> /reset

| Resetting state.

jshell> /list

jshell>

jshell> String context = "JavaOne 2017"

context ==> "JavaOne 2017"

| created variable context : String

jshell> /reload

| Restarting and restoring state.

-: String context = "JavaOne 2017";

jshell> /list

1 : String context = "JavaOne 2017";

# linux> /set editor /usr/bin/vim

# windows> /set editor c:\Program Files\NotePath\notepath.exe

# macOS> /set editor --wait open -a 'Sublime Text'

$ jshell --startup PRINTING| Welcome to JShell -- Version 9| For an introduction type: /help intro

jshell> print("YAY!")YAY!

$ jshell --startup DEFAULT JAVASE PRINTING

$ jshell --startup DEFAULT JAVASE PRINTING

jshell> /exit

| Goodbye

jshell> /exi

| Goodbye

jshell> /ex

| Goodbye

jshell> CTRL + C + D

| Goodbye

static.rainfocus.com...jshell> int age = 20 age ==> 20 jshell> age + 2 $2 ==> 22 jshell> 4 * $2 $3...

Documents

Transcript of static.rainfocus.com...jshell> int age = 20 age ==> 20 jshell> age + 2 $2 ==> 22 jshell> 4 * $2 $3...