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

code


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


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


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

code

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


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


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


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

Technology

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