nashorn: javascript running on java vm (english)

Copyright © 2014, Oracle and/or its affiliates. All rights reserved.1

JavaScript Running On JavaVM: Nashorn

NISHIKAWA, Akihiro

Oracle Corporation Japan


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described for Oracle’s products remains at the sole discretion of

Oracle.

Copyright © 2014, Oracle and/or its affiliates. All rights reserved.3 Copyright © 2013, Oracle and/or its affiliates. All rights reserved.

Agenda Nashorn

Server Side JavaScript

Nashorn in the future


Nashorn


NashornJavaScript Engine running on Java VM


Backgrounds

Replacing Rhino

– Concerns about security, performance, and so on

Proof of Concept for InvokeDynamic (JSR-292)

Atwood's law

Any application that can be written in JavaScript will

eventually be written in JavaScript.


Scope of Project NashornJEP 174

ECMAScript-262 Edition 5.1 compliant

Support for javax.script (JSR 223) API

Interaction between Java and JavaScript

Newly introduced command line tool (jjs)


Java VM

Scripting Engine

(Nashorn)

Scripting API

(JSR-223)

JavaScript codeJava code

Other runtime

Other APIs jjs


$JAVA_HOME/bin/jjs

$JAVA_HOME/jre/lib/ext/nashorn.jar


ECMAScript-262 Edition 5.1 compliant


Out of scope of Project Nashorn

ECMAScript 6 (Harmony)

– Generators

– Destructuring assignment

– const, let, ...

DOM/CSS and related libraries

– jQuery, Prototype, Dojo, …

Browser API and browser emulator

– HTML5 canvas, HTML5 audio, WebGL, WebWorkers...


Examples


Invoke Nashorn from Java

ScriptEngineManager manager= new ScriptEngineManager();

ScriptEngine engine= manager.getEngineByName("nashorn");

engine.eval("print('hello world')");

engine.eval(new FileReader("hello.js"));


Invoke Nashorn from JavaInvoke script function from Java

engine.eval("function hello(name) {print('Hello, ' + name)}");

Invocable inv=(Invocable)engine;

Object obj=inv.invokeFunction("hello","Taro");


Invoke Nashorn from JavaImplement an interface with script function

engine.eval("function run(){

print('run() called’)

}");

Invocable inv =(Invocable)engine;

Runnable r=inv.getInterface(Runnable.class);

Thread th=new Threads(r);

th.start();

th.join();


Invoke Java/JavaFX from Nashorn

print(java.lang.System.currentTimeMillis());

jjs -fx ...


Nashorn for ScriptingAdditional feature for scripting use

-scripting option

Here document

Back quote

String Interpolation

...


Nashorn Extensions


Nashorn ExtensionsThe following topics are covered in this session.

How to get references of Java type

How to access properties of Java objects

Relationship among Lambda, SAM, and Script function

Scope and context


Java type


How to get references of Java typeExpression in Rhino (This expression is valid in Nashorn)

var hashmap=new java.util.HashMap();

Or

var HashMap=java.util.HashMap;var hashmap=new HashMap();


How to get references of Java typeRecommended expression in Nashorn

var HashMap=Java.type('java.util.HashMap');var hashmap=new HashMap();


Java.typeClass or Package?

java.util.ArrayList

java.util.Arraylist


Java ArrayExpression in Rhino

var intArray=java.lang.reflect.Array.newInstance(

java.lang.Integer.TYPE, 5);

var Array=java.lang.reflect.Array;

var intClass=java.lang.Integer.TYPE;

var array=Array.newInstance(intClass, 5);


Java ArrayExpression in Nashorn

var intArray=new(Java.type("int[]"))(5);

var intArrayType=Java.type("int[]");var intArray=new intArrayType(5);


Access properties ofJava objects


Using getter and setter

var HashMap=Java.type('java.util.HashMap');

var map=new HashMap();

map.put('size', 2);

print(map.get('size')); // 2


Directly



map.size=3;

print(map.size); // 3

print(map.size()); // 1


Using Associative Array



map['size']=4;

print(map['size']); // 4

print(map['size']()); // 1


Lambda, SAM, and Script function


Lambda, SAM, and Script functionNashorn converts a script function to a lambda object or any SAM

interface implementing object automatically.

var timer=new java.util.Timer();

timer.schedule(

function() { print('Tick') }, 0, 1000);

java.lang.Thread.sleep(5000);

timer.cancel();


Lambda, SAM, and Script functionAny Java object which is an instance of lambda type can be treated like a

script function.

var JFunction=Java.type('java.util.function.Function');

var obj=new JFunction() {

// x->print(x*x)

apply: function(x) { print(x*x) }

}

print(typeof obj); //function

obj(9); // 81 like Script function


Scope and Context


Scope and Contextload and loadWithNewGlobal

load

– Load scripts in the same global scope.

– If same name variables are in the original scripts and

loaded scripts, Corruption of each variable may happen.

loadWithNewGlobal

– Load scripts in another global scope newly created.

– Even if same name variables are in the original scripts

and loaded scripts, Corruption of each variable may not

happen.


Scope and ContextScriptContext contains one or more Bindings each associated each jsr223

"scope".ScriptContext ctx=new SimpleScriptContext();

ctx.setBindings(engine.createBindings(),ScriptContext.ENGINE_SCOPE);

Bindings engineScope=ctx.getBindings(ScriptContext.ENGINE_SCOPE);

engineScope.put("x", "world");

engine.eval("print(x)", ctx);


Scope and ContextUsing with clause and JavaImporter

with(new JavaImporter(java.util, java.io)){

var map=new HashMap(); //java.util.HashMap

map.put("js", "javascript");

map.put("java", "java");

print(map);

....

}


Others

Convert between Java array and JavaScript array

– Java.from

– Java.to

Extend Java class and access super-class

– Java.extend

– Java.super

and so on...


Java EE for Next Generation ApplicationsDeliver HTML5, Dynamic and Scalable Applications

Web

So

ckets

Avata

r


Evolution of Web application architectureRequest-Response and Multi-page application

Java EE/JVM

Presentation

(Servlet/JSP)

Business

Logic

Backend

ConnectivityBrowser


Evolution of Web application architectureUse Ajax (JavaScript)

Java EE/JVM

Connectivity(REST, SSE)

Presentation(Servlet/JSP, JSF)

Business

Logic

Backend

ConnectivityBrowser

JavaScript


Modern Web application architectureRather connectivity than Presentation – Single Page Application

Java EE/JVM

Connectivity(WebSocket,

REST, SSE)

Presentation(Servlet/JSP, JSF)

Business

Logic

Backend

ConnectivityBrowser

View

Controller

JavaScript


How about Node.js?


Mobile-enabled existing services with Node.js

Node.js

JavaScript

REST

SSE

WebSocket

Browser

View

Controller

JavaScript


How aboutNode.js on JVM?


Mobile-enabled existing services with NodeNode running on Java VM

Java EE/JVM

Node

Server

Business

Logic

Backend

Connectivity

Client

JavaScriptBrowser

View

Controller

JavaScript


Avatar.js


Avatar.jsOld name is "node.jar"

Able to use almost all of modules available on Node.js

– Express, async, socket.io, ...

Some modules are required to modify.

– Automatically recognize modules downloaded with

npm.

Pros.

– Leverage node programming model

– Leverage existing Java assets, knowledge, and tools


Avatar.js = Node + JavaLeverage Java technologies including Threads

JavaJavaScript

com.myOrg.myObj

java.util.SortedSet

java.lang.Thread

require('async')

postEvent

Node App


Avatar


AvatarServer side JavaScript services framework

Provide data transmission features via REST, WebSocket,

and Server Sent Event (SSE)

Leverage event-driven programming model and

programming modules of Node.js

Integrate with Enterprise Features (Java EE)


*.html

*.js

*.css

HTTP

Application

Services

Avatar Modules

Node Modules

Avatar.js

Avatar Runtime

Avatar Compiler

Server Runtime (Java EE)

JDK 8 / Nashorn

Application

Views

REST/WebSocket/SSE

Avatar (Avatar EE)

Change

Notification

Data


HTTP

REST/WebSocket/SSE

Avatar Compiler

Application

Views

*.html

*.js

*.css

Application

Services

Avatar Modules

Node Modules

Avatar.js

Avatar Runtime


JDK 8 / Nashorn

Architecture (Server Side)

Change

Notification

Data


Avatar Service

Java

JavaS

cri

pt

HTTP Load Balancer

Services

Shared State

Services Services

Change

Notification

Data


Avatar Runtime


Avatar Modules

Node Modules

Avatar.js

*.html

*.js

*.css

Application

Services

JDK 8 / Nashorn

Architecture (Client Side)

Change

Notification

Data

HTTP

REST/WebSocket/SSE

Application

Views

Avatar Compiler


Avatar and Avatar.jsprogress steadily.



Bytecode Persistence (JEP 194)

http://openjdk.java.net/jeps/194

Optimistic Typing

Others

http://openjdk.java.net/jeps/194


Summary


Key takeaways

Nashorn

– Tightly integrated with Java

– Pay attention to different expression when migrating

artifacts from Rhino to Nashorn

– Progress steadily (performance improvement, new

features, compliant against new standards)


– Avatar.js and Avatar are on-going.

– Please feedback!


Appendix


Source code walk through

Shell jjs uses mainly.

Compiler generates classes (bytecode) from sources.

Scanner Create tokens from sources.

Parser Create AST/IR from tokens.

IR Elements of scripts

Codegen Create script class bytecode from AST/IR

Objects Runtime elements (Object, String, Number, Date, RegExp)

Scripts Classes including codes for scripts

Runtime Runtime tasks

Linker Binds callees on runtime based on JSR-292 (InvokeDynamic)

Dynalink Searching for best methods (available across languages)


Nashorn Documentshttp://wiki.openjdk.java.net/display/Nashorn/Nashorn+Documentation

Java Platform, Standard Edition Nashorn User's Guide

http://docs.oracle.com/javase/8/docs/technotes/guides/scripting/nash

orn/

Scripting for the Java Platform

http://docs.oracle.com/javase/8/docs/technotes/guides/scripting/

Oracle Java Platform, Standard Edition Java Scripting Programmer's

Guide

http://docs.oracle.com/javase/8/docs/technotes/guides/scripting/prog_

guide/

http://docs.oracle.com/javase/8/docs/technotes/guides/scripting/nashorn/

http://docs.oracle.com/javase/8/docs/technotes/guides/scripting/

http://docs.oracle.com/javase/8/docs/technotes/guides/scripting/prog_guide/


Nashornhttp://openjdk.java.net/projects/nashorn/

OpenJDK wiki – Nashorn

https://wiki.openjdk.java.net/display/Nashorn/Main

Mailing List

[email protected]

Blogs

– Nashorn - JavaScript for the JVM

http://blogs.oracle.com/nashorn/

– Nashorn Japan

https://blogs.oracle.com/nashorn_ja/

http://openjdk.java.net/projects/nashorn/

https://wiki.openjdk.java.net/display/Nashorn/Main

mailto:[email protected]

http://blogs.oracle.com/nashorn/

https://blogs.oracle.com/nashorn_ja/


Avatar.js

Project Page

https://avatar-js.java.net/

Mailing List

[email protected]

https://avatar-js.java.net/



Avatar

Project Page

https://avatar.java.net/

Mailing List

[email protected]

https://avatar.java.net/


nashorn: javascript running on java vm (english)

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