boldly go where the java programming language has never gone before

Boldly gowhere the Java programming languagehas never gone before

Geert Bevin, Senior Developer, Terracotta Inc.

TS-6213

2008 JavaOneSM Conference | java.sun.com/javaone | 2

Learn that you don't have to master new languages, tools and libraries to deliver applications that go much further than what the standard Java™ Platform provides

Who is Geert Bevin?

senior developer at Terracotta (http://terracotta.org)founder of Uwyn (http://uwyn.com)founder of RIFE (http://rifers.org)contributor to many open-source projects:Terracotta, RIFE, OpenLaszlo, Gentoo Linux,Bla-bla List, Drone, ...Sun Java Championcreator of native Java language continuationsbiker and gamer

Agenda

Java programming language != Java Virtual Machine (JVM™) != Java platformTerracottaRIFE ContinuationsGoogle Web ToolkitGoogle Android

Key differences

The Java programming language provides a syntax that allows the expression of application logicThe JVM provides a runtime environment that abstracts away the operating system and hardware differencesThe Java platform bundles the Java programming language and the JVM with tools and libraries to provide a complete development and runtime solution

Different purposes

The Java programming language is for developmentThe JVM is for the execution of byte codeThe Java platform provides javac which compiles Java code to byte code

This is what you use every day …

… but it doesn’t have tobe this way

You can change the language

Another language can be used for developmentFor example:• Groovy• JavaFX™ script• Scala• JRuby• Jython• ...

You can change the tooling

Another tool can be used to create byte codeFor example:• ASM• AspectJ• BCEL• groovyc• ...

You can change the runtime

Another runtime can be used to execute your logicFor example:• GCJ• Web browser• Dalvik virtual machine• …

Today’s focus

Any variation on this theme is possibleAny of the layers can be replaced, extended or modifiedToday we'll focus on the Java programming language as the constant

Disclaimer

The technologies in this presentation are being covered from a 'boldness' perspective. No judgment is made on

whether they're a good solution nor how they compare to alternatives. This presentation is also not intended to be a

comprehensive overview of their capabilities

Agenda

Java programming language != JVM != Java platformTerracottaRIFE ContinuationsGoogle Web ToolkitGoogle Android

Agenda

What is Terracotta?

Open Source Clustering for the Java Platform

Scalability and Availability for the JVM

Terracotta Overview

Terracotta’s approach

'Regular' Clustering• Scale out is complex• Requires custom Java code

Different approach• Cluster the JVM software• Eliminate need for custom

Main features

Heap level replication• Declarative• No serialization• Fine grained / field Level• Only where resident

Large virtual heaps• As large as available disk• Dynamic paging

JVM coordination• Distributed synchronized• Distributed wait()/notify()• Fine grained locking

Management• Runtime visibility• Data introspection• Cluster monitoring

Terracotta Essential FeaturesAnimation

Terracotta Examples

Example of shared stateHello World

Hello World- tutorial/HelloWorld.java

Hello World - tc-config.xml

Demo Terracotta Shared StateHello World

Hello World - trying it out

Start the server:$ start-tc-server.shStart a client:$ dso-java.sh -Dtc.config=tc-config.xmltutorial.HelloWorldOutput:Hello Thu Dec 13 17:46:58 CET 2007After starting the 2nd client:Hello Thu Dec 13 17:46:58 CET 2007Hello Thu Dec 13 17:47:06 CET 2007The state is preserved in the server between executions

Example of coordinationEnhanced Hello World

using java.util.concurrent

Coordination - HelloWorldConcurrent.java

Coordination - tc-config-concurrent.xml

Demo Terracotta CoordinationEnhanced Hello World

Coordination - trying it out

Start the server:$ start-tc-server.shStart a client:$ dso-java.sh -Dtc.config=tc-config-concurrent.xml

-Dnodes=2 tutorial.HelloWorldConcurrentIt just hangs thereAfter starting the 2nd client:Hello Thu Dec 13 19:12:38 CET 2007Hello Thu Dec 13 19:13:56 CET 2007The cyclic barrier is clustered across JVMs

Terracotta’s Boldness

Terracotta's Boldness

Plug into the JVM with a bootjarTranslate threads to cluster nodesModify getfield, putfield, monitorenter, monitorexit byte code instructions to work across the clusterJava Memory Model as a contract for accessing shared state and coordination across the cluster

Agenda

What is RIFE?

Full-stack component framework toquickly and consistently develop and

maintain Java web applications

What are continuations?

… continuations are like

Save Game

… Save Game

can be performed at certain locations in the game(or anywhere, depending on the type of game)captures the progress and your possessionsseveral saved games can exist at once

… but they are also like

Load Game

… Load Game

retrieve any saved gameload the saved gamerestore the progress and your possessionsresume exactly where you left off

… all we have to do is replace

Game ApplicationSaved Game Continuation

Progress LocationPossession State

… Pausecan be performed at certain locations in the gamecaptures the progress and your possessionsseveral saved games can exist at once

… Resumeretrieve any saved gamesload the saved gamerestore the progress and your possessionsresume exactly where you left off

gamethe progress your possessions

saved games

saved gamessaved game

the progress your possessions

applicationthe location the state

continuationcontinuation

the location the state

continuations

Concretely

Concretely : pseudo code

Program output isLet's call this backwardsContext and location are stored in a variableMultiple continuations can be active at once

Continuations ExampleNumber guessing game(as a web application)

Number Guessing - Game.java

Demo ContinuationsNumber Guessing Game Running & Debugging

RIFE’s Boldness

Java method calls are trapped at runtime when classes are loaded to rewrite the code sections they're executing in (pause(), call(), answer())Intuitive state handling, requiring no serializationRegular Java language statements direct application control flowRegular Java development tools like debuggers and IDEs can be used to develop, document and debug application control flowContinuation trees for backward and forward stepping

Agenda

What is Google Web Toolkit?

Create AJAX applications in the Java programming language using regular Java tools and deploy them to browser-

compliant HTML and Javascript™ technology

Google Web Toolkit Overview

Google Web Toolkit approach

'Regular' Ajax Dev• Write Javascript code and

DHTML• Learn all the intricacies

Different approach• Write Ajax applications in the

Java platform• Compile Java code to Javascript

Ajax Libraries

Javascript versions Browser differences

Client-side debuggers

Smart text editors Resource packaging

Difficult to test

Design RPC API and format

Google Web Toolkit (GWT)

use Java platform, standard APIs and your regular tools

GWT’s main features

Two main execution modes• Hosted mode

• Executed with the JVM, no generated Javascript source code• Embedded browser hooks into Java libraries• Code-test-debug as regular Java applications

• Web mode• Compiles Java source code to Javascript source code• Runs inside browser without plugins

Standardized RPC• Implement RemoteService interface• Relies on serialization for arguments and return values• Supports asynchronous method calls

GWT Examples(with Eclipse)

Hello World

GWT Hello World

Create a new project and generate the required files

Import project into Eclipse

Hello World - com/client/HelloWorldApp.java

Hello World - com/public/HelloWorldApp.html

Demo GWTHello World

RPC Services

com/client/GreeterService.java

com/services/GreeterServiceImpl.java

com/client/GreeterServiceAsync.java

RPC GWT Module - com/RpcApp.gwt.xml

RPC App - com/client/RpcApp.java 1/2

RPC App - com/client/RpcApp.java 2/2

Demo GWTRPC

GWT’s Boldness

Two execution modes simplify both development and deploymentBrowser is hooked into Java libraries to provide real debugging during hosted modeThe Java source code is compiled to the Javascript source code during web mode to hide the difficulties of Ajax/DHTML development

Agenda

What is Google Android?

A platform for mobile devices wheresoftware is written in the Java

language and run on Dalvik, a customvirtual machine for embedded use

Google Android Overview

Google Android approach

'Regular' Mobile Dev• Proprietary platform• Java™ Platform, Micro Edition

(Java ME) is just another application

• Java applications run in the same virtual machine

Different approach• Open-source platform• All applications in Java

programming language• Dedicated virtual machine

per application

Google Android Architecture

Demo Google AndroidToo many snippets and resources toshow code in slides

Google Android’s Boldness

Program everything in the Java programming languageOnly use Android's Java Platform Runtime Environment (JRE), which includes supported library classesCompile with javac and convert to Android bytecode for the Dalvik VM (.dex files)Debug through the Dalvik Debug Monitor Server (DDMS) which forwards ports from the emulator or device to the IDE

Agenda

Conclusion

Using just the Java language you're able to do:• Transparent Clustering and Coordination:

Terracotta (http://www.terracotta.org)• Intuitive application control flow:

RIFE Continuations (http://rifers.org)• Ajax client application development:

Google Web Toolkit (http://code.google.com/webtoolkit)• First-class mobile application development:

Google Android (http://code.google.com/android)

Without learning new languages and tools, all these possibilities open up

Boldly go where the Java programming language has never gone beforeGeert Bevin

http://terracotta.org - http://rifers.org

boldly go where the java programming language has never gone before

java2008 javaonesm conference

gamer2008 javaonesm

java programming languageand

java platform scalability

java virtual machine

custom java code

java code tobyte code

terracotta http

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