E V R O A A I O D L N P T

Transcription

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2 E V R O A A I O D L N P T

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4 # 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

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7 $ jshell Welcome to JShell -- Version 9 For an introduction type: /help intro jshell> /help

8 jshell> int age = 30 age ==> 30 jshell> age = 31 age ==> 31 jshell> int age = 29 age ==> 29 jshell> /vars /v int age = 29 jshell> rate = 20 Error: cannot find symbol symbol: variable rate rate = 20 ^--^ jshell> int rate = 20 rate ==> 20

9 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;

10 jshell> int age = 20 age ==> 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 : 4 * $2 4 : "Java 9 hack day" jshell> /3 4 * $2 $5 ==> 88 jshell> $3 $3 ==> 88

11 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.

12 jshell> Math.random() $8 ==> jshell> /! Math.random() $9 ==> jshell> /! Math.random() $12 ==> jshell> int age = 20; age ==> 20 2 jshell> Math.random() $2 ==> jshell> age = 21 age ==> 21 jshell> /-2 Math.random() $5 ==>

13 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)

14 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

15 jshell> /t Figure class Figure jshell> /edit Figure created class Circle jshell> /t class Figure class Circle jshell> /edit Figure created class Rectangle

16 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 is declared

17 jshell> class Employee {...> private String name;...>...> Employee(String name) {...> this.name = name;...> }...>...> String name() {...> return name;...> }...>...> } jshell> new Employee("Joe") $2 ==> Employee@2f686d1f jshell> $2. <tab> equals() getclass() hashcode() name() notifyall() notify() tostring() wait() jshell> $2.name() $3 ==> "Joe" created class Employee

18 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 $ ls employeesnippets

19 $ ls employeesnippets $ jshell jshell> /open employeesnippets jshell> joe.name() $5 ==> "Joe" jshell> joe.surname() $6 ==> "Doe" 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")

20 jshell> /env -class-path mongo-java-driver jar Setting new options and restoring state. jshell> /env --class-path mongo-java-driver jar jshell> import com.mongodb.mongoclient jshell> MongoClient mongoclient = new MongoClient()

21 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>

22 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";

23 # linux > /set editor /usr/bin/vim # windows > /set editor c:\program Files\NotePath\notepath.exe # macos > /set editor --wait open -a 'Sublime Text'

24 jshell> /set feedback /set feedback normal Available feedback modes: concise normal silent verbose jshell> /set feedback verbose Feedback mode: verbose jshell> int age = 20 age ==> 20 created variable age : int jshell> /set feedback silent -> int age = 20 ->

25 $ 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

26 jshell> /exit Goodbye jshell> CTRL + C + D Goodbye jshell> /exi Goodbye jshell> /ex Goodbye

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