Monday, June 08, 2009

JavaOne 2009 Day Five (05/06/2009)

The final day of JavaOne 2009 began with a General Session titled "James Gosling's Toy Show". This featured the creator of Java playing host to a long line of people representing organisations that were using Java technology in highly innovative and useful ways. Many of them got Duke's Choice awards.

First up was Ari Zilka (CEO, Terracotta) who was given the award for a tool that makes distributed JVMs appear like one, thereby providing a new and different model of clustering and scalability. Terracotta also allows new servers and JVMs to be added on the fly to scale running Java applications.

Brendan Humphreys ("Chief Code Poet", Atlassian) received the award for Atlassian's tool Clover. [Brendan is from Atlassian's Sydney office, and I've met him there on occasion when Atlassian hosts the Sydney Java User Group meetings.] Clover is about making testing easier by identifying which tests apply to which part of an application. When changing part of an application, Clover helps to run only the tests that apply to that part of the code.

Ian Utting, Poul Henriksen and Darin McCall of BlueJ were recognised (though not with a Duke's Choice award) for their work on Greenfoot, a teaching tool for children. Most of their young users are in India and China, but it's not clear how many there are, because they only interact with the Greenfoot team through their teachers.

Mark Gerhard (CEO of Jagex) was called up to talk about RuneScape. [Mark Gerhard received the Duke's Choice Award on Day 2, as diligent readers of this blog would remember.] This time, the focus was not on the game itself, but on the infrastructure it took to run it. According to Gerhard, Jagex runs the world's second-biggest online forum. There is no firewall in front of the RuneScape servers (!), so they get the full brunt of their user load. The servers haven't been rebooted in years. Jagex had to buid their own toolchain, because a toolchain needs to understand how to package an application for streaming, which off-the-shelf equivalents don't know to do. Jagex runs commodity servers (about 20?) and their support team has just 3 people. Considering that their user base numbers 175 million (10 million of whom are active at any time), this is a stupendous ratio. Of course, Jagex has about 400 other staff, mainly the game developers. Jagex builds their libraries and frameworks in-house, and they maintain feature parity with their commercial competitor, Maya. I found it curious that Gerhard was cagey when asked which version of Java they used. Why would that need to be a secret? All he would say was that we could guess the version from the fact that their servers hadn't been rebooted in 5 years.

By way of vision, Gerhard said that OpenGL would be standard on cell phones in a year, and Jagex's philosophy is that "There's no place a game shouldn't be".

The next people on stage were two researchers from Sun itelf, - Simon Ritter and Angela Caicedo. [Caicedo had been at the Sydney Developer Day only a couple of weeks earlier.] Ritter demonstrated a cool modification of the Wii remote control, especially its infra-red camera. The remote talks Bluetooth to a controller. I didn't grasp the details of how the system was built, although I heard the terms Wii RemoteJ and JavaFX being mentioned. Ritter held a screen in front of him, and a playing card was projected onto it. Nothing hi-tech there. When he rotated the screen by 90 degrees, the projected image rotated as well, which was interesting. But what brought applause was when he flipped the screen around, and the projected image switched to the back of the card! He also showed how a new card could be projected onto the screen by just shaking the screen a bit (shades of the iPod Shuffle there).

Caicedo demonstrated a cool technology that she thought might be useful to people like herself who had young children with a fondness for writing on walls. With a special glove that had a embedded infra-red chip, she could "draw" on a screen with her finger, because a projector would trace out whatever she was drawing based on a detection of the position of her finger at any given time. The application was a regular paint application, allowing the user to select colours from a toolbar and even mix them on a palette.

Tor Norbye (Principal Researcher, Sun) then gave the audience a sneak preview of the JavaFX authoring tool that has not yet been released. Very neat animations can be designed. It's possible to drag an image to various positions and map them to points in time. Then the tool interpolates all positions between them and shows an animation that creates an effect of smooth motion, bouncing images, etc. There are several controls available, like buttons and sliders, and it's possible to visually map between the actions of controls and behaviours of objects. It reminded me of the BeanBox that came with Java 1.1, which showed how JavaBeans could be designed to map events and controls. The lists of events and actions appear in dropdowns through introspection.

There's no edit-compile cycle, which speeds up development. Norbye showed how the same animation could be repurposed to different devices and form factors. There's a master-slave relationship between the main screen and the screens for various devices, such that any change made to the main screen is reflected in the device-specific screens, but any specific overrides made on a device-specific screen remain restricted to that screen alone.

Fritjof Boger-Engelhardtsen of Telenor gave us a demo on a technology I don't pretend to understand. In the mobile world, the SIM card platform is very interesting to operators. The next generation of SIM cards will be TCP/IP connected nodes, with motion sensors, WiFi, etc., embedded within the card. It will be a JavaCard 3 platform. It's possible to use one's own SIM card to authenticate to the network. FB-E gave us a demo of a SunSpot sensor device connected to a mobile phone and being able to control the phone's menu by moving the SunSpot. The phone network itself is oblivious to this manipulation. More details are available at http://playsim.dev.java.net.

Brad Miller (Associate Professor, Worcester Polytechnic Institute Robotics Research Center) and Derek White (Sun Labs) showed some videos of the work done by High School students. Given a kit of parts, the students have to put together robots to participate in the "US First", an annual robotics competition. A large part of the code has been ported across from C/C++ to Java, and the project is always on the lookout for volunteer programmers. Interested people can go to www.usfirst.org. WPI got a Duke's Choice award for this.

Sven Reimers (System Engineer and Software Architect, ND Satcom) received a Duke's Choice award for the use of Java in analysing the input of satellites.

Christopher Boone (President and CEO, Visuvi, Inc) showed off the Visuvi visual search enine. Upload an image and the software analyses it on a variety of aspects and can provide deep insights. Simple examples are uploading images of paintings and finding who the painter was. More useful and complex uses are in the area of cancer diagnosis. Visuvi improves the quality and reduces the cost of diagnosis of prostate cancer. The concordance rate (probablity of agreement) between pathologists is only about 60%, and the software is expected to achieve much better results. The Visuvi software performs colour analysis, feature detection and derives spatial relationships. There's some relationship to Moscow State University that I didn't quite get. At any rate, Visuvi is busy scanning in 400 images a second (at 3000 megapixels and 10 MB each)!



Sam Birney and Van Mikkel-Henkel spoke about Mifos, a web application for institutions that deal in providing microfinance to poor communities. Microfinance is inspired by the work done by Mohammed Yunus of Grameen Bank. This is an Open Source application meant to reduce the barriers to operation of cash-strapped NGOs. The challenge is to scale. Once again, volunteers are wanted: http://www.mifos.org/developer/ , and not just for development but also for translation into many relatively unknown languages. Mifos won a Duke's Choice Award.



Manuel Tijerino (CEO, Check1TWO) told of how many of his musician friends were struggling to find work at diners. So he created a JavaFX based application that allows artistes to upload their work to the Check1TWO site, and it's automatically available on any Check1TWO "jukebox" at any bar or disco. Regular jukeboxes are normally tied up in studio contracts, so the Check1TWO jukeboxes provide a means for struggling artistes to reach over the heads of the studios and connect directly with their potential audiences.

Zoltan Szabo and Balazs Lajer (students at the University of Pannonia, Hungary) showed off their project that won the first prize at RICOH's student competition. Theirs is a Java application that runs on a printer/scanner and is capable of scoring answer sheets.

Marciel Hernandez (Senior Engineer, Volkswagen Electronics Research Lab and Stanford University) and Greg Follella (Distinguished Engineer, Sun) talked about Project Bixby. This is about automating the testing of high-speed vehicles through "drive-by-wire". The core of the system is Java RTS (Run-time System). The primary focus is improving safety. Stanford University is building the control algorithms. It should be possible to control the car when unexpected things happen, which especially happens on dirt racetracks. There's no need to put a test driver at risk. Project Bixby leads to next-generation systems that are faster, such as more advanced ABS (Anti-lock Braking System) and newer stability control systems).

Finally, there was a video clip of the LincVolt car, which turns a classic Lincoln Continental into a green car like the Prius, but with some differences. The Prius has parallel electrical and petrol engines. The LincVolt has batteries driving the wheels all the time, with the petrol engine only serving to top up the battery pack when it starts to run down. What's the connection with Java? The control systems and visual dashboard are all Java.

This concluded the General Session.

I then attended a session titled "Real-World Processes with WS-BPEL" by Murali Pottlapelli and Ron Ten-Hove. The thrust of the whole session was that WS-BPEL as a standard was incomplete and that real-world applications need more capabilities than WS-BPEL 2.0 delivers. A secondary theme of the session was that an extension called BPEL-SE developed for OpenESB is able to address the weaknesses of WS-BPEL.

[My cynical take on this is that every vendor uses the excuse of an anaemic spec to push their own proprietary extensions. If there is consensus that WS-BPEL 2.0 doesn't cut the mustard, why don't the vendors sit down together and produce (say) a WS-BPEL 3.0 spec that addresses the areas missing in 2.0? I'm not holding my breath.]

The structure was fairly innovative. Ten-Hove would talk about the failings of the standard and Pottlapelli would then describe the solution implemented in BPEL-SE. [The session would have been far better if Pottlapelli had been able to communicate more effectively. I'm forced to the painful realisation that many Indians, while being technically competent, fail to impress because their communication skills are lacking.]

These are the shortcomings of WS-BPEL 2.0 that are addressed by BPEL-SE:

- Correlation is hard to use, with multiple artifacts to define and edit. BPEL-SE provides a correlation wizard that hides much of this complexity.
- Reliability is not defined in the context of long-running business processes susceptible to crashes, maintenance downtime, etc. BPEL-SE defines a state machine where the state of an instance's execution is persisted and can be recovered on restart without duplication.
- High Availability is not defined. BPEL-SE on GlassFish ESB can be configured to take advantage of the GlassFish cluster, where instances migrate to available nodes.
- Scalability is an inherent limitation when dealing with long-running processes that hold state even when idle. BPEL-SE defines "dehydrate" and "hydrate" operations to persist and restore state. As the dehydrate/hydrate operation is expensive, two thresholds are defined (the first to dehydrate variables alone, and the next to dehydrate entire instances).
- Retry is clumsy in WS-BPEL, because the <invoke> operation doesn't support retries. Building retry logic into the code obscures the real business logic. BPEL-SE features a configurable number of retries and a configurable delay between retries. It also supports numerous actions on error.
- Throttling is difficult to achieve in WS-BPEL, which makes the system vulnerable to denial of service attacks and bugs that result in runaway processes. BPEL-SE can limit the number of accesses to a "partnerlink" service node, even across processes. This helps to achieve required SLAs.
- Protocol headers are ignored in WS-BPEL by design, as it is meant to be protocol-agnostic. However, many applications place business information in protocol headers such as HTP and JMS. BPEL-SE provides access to protocol-specific headers as an extension to <from> and <to> elements. Protocols such as HTTP, SOAP, JMS (strictly speaking, this isn't a protocol but an API) and file headers.
- Attachments are non-standard in WS-BPEL, with some partners handling document routing inline and some as an attachment. BPEL-SE adds the extensions "inlined" and "attachment" to the <copy> element.
- BPEL extensions fail because it relies on XPath, and XPath 1.0 has a limitation in that false is interpreted as true (boolVar is a non-empty node). BPEL-SE uses JXPath, and is enhanced to be schema-aware. False is not interpreted as true, and integers do not end in ".0".
- XPath limitations hamper WS-BPEL, because XPath has a limited type system, it is impossible to set a unique id on the payload, it's a challenge to extract expensive items in a purchase order document if it spans multiple activities, etc. Any kind of iteration across an XML structure is difficult, and this is partly due to the limitations of XPath and partly due to those of BPEL. With BPEL-SE, Java calls can be embedded in any XPath expression, with syntax adapted from Xalan. It also supports embedded JavaScript (Rhino with E4X), which makes XML parsing much easier.
- Fault handling is problematic in WS-BPEL because standard faults have no error messages, which makes them hard to debug. Standard and non-standard faults can be hard to distinguish. This complicates fault handlers, requiring multiple catches for standard faults. The WSDL 1.1 fault model has been carried too far. BPEL-SE fault handler extensions propagate errors and faults not defined in WSDL as system faults. Associated errors are wrapped in the fault message. Standard faults are associated with a fault message and failure details like activity name are carried along. BPEL-SE catches all standard and system faults.

I asked the presenters if they were making the case that BPEL-SE had addressed all the limitations of WS-BPEL or if they felt there were some shortcomings that still remained. Ten-Hove's answer was that subprocesses were a lacuna that hadn't yet been addressed.

My next session was "Cleaning with Ajax: Building Great Apps that Users Will Love" by Clint Oram of SugarCRM. I regret to say that this session was short on subject matter and ended in just half an hour. The talk seemed to be more a sales pitch for SugarCRM than a discussion of Ajax principles. Even the few design principles that were discussed were fairly commonsensical and did not add much insight.

For what it is worth, let me relate the points that sort of made sense.

Quite often, designers are asked to "make the UI Ajax". This doesn't say what is really expected. Fewer page refreshes? Cool drag-and-drop? Animation?

There are also some downsides of Ajax:
- Users get lost (browser back and forward buttons and bookmarks are broken, the user doesn't always see what has changed on the page, and screen elements sometimes keep resizing constantly, irritating the user)
- There are connection issues (it can be slow, the data can't be viewed offline, and applications often break in IE6)
- There are developer headaches (mysterious server errors (500), inconsistent error handling, PHP errors break Ajax responses)

Some design questions need to be asked before embarking on an Ajax application:
- Does the user really want to see the info?
- Will loading this info be heavy on the server?
- Does the info change rapidly?
- Is there too much info?

The "lessons learned", according to Oram, are:

- Use a library like YUI, Dojo or Prototype instead of working with raw JavaScript.
- Handle your errors, use progress bars to indicate what is happening, don't let the application seem like it's working when there has been an error.
- Ajax is a hammer, and not every problem is a nail.
- Load what you need, when you need it.

As one can see, there was nothing particularly insightful in this talk, and it was a waste of half-an-hour.

One interesting piece of information from this session was that IBM WebSphere sMash (previously Project Zero) is a PHP runtime that runs on the JVM and provides full access to Java libraries.

SugarCRM 5.5 Beta is out now, and adds a REST API to the existing SOAP service API.

I'm not a fan of SugarCRM. The company's "Open Source" strategy is basically to provide crippleware as an Open Source download, and to sell three commercial versions that do the really useful stuff. I don't know how many people are still fooled by that strategy.

The next session I attended was quite possibly the best one I have attended over these five days. It was called "Resource-Oriented Architecture and REST" by Scott Davis (DavisWorld Consulting, Inc).

Unfortunately, the talk was so engrossing that I forgot to take notes in many places, so I cannot do full justice to it here :-(. Plus, Davis whizzed through examples so fast I didn't have time to transcribe them fully, and lost crucial pieces of code.

Davis is the author of the columns "Mastering Grails" and "Practically Groovy" on IBM Developerworks. He's also a fan of David Weinberger's book "Small Pieces Loosely Joined", which describes the architecture of the web. Although ten years old, the book is still relevant today. [David Weinberger is also the author of The Cluetrain Manifesto.]

I knew Groovy was quite powerful and cool, but in Davis's hands it was pure magic. In a couple of unassuming lines, he was addressing URLs on the web and extracting information that would have taken tens of lines with SOAP-based Web Services. I must have transcribed them incorrectly, because I can't get them to work on my computer. I'll post those examples when I manage to get them working.

A really neat example was when he found a website that provided rhyming words to any word entered on a form. He defined a "metaclass" method on the String class to enable it to provide rhymes by invoking the website. Then a simple statement like "print 'java'.rhyme()" resulted in "lava".

As Davis said, REST is the SQL of the Web.

Davis then talked about syndication with the examples of RSS and Atom. Three things draw one in (chronology (newest first), syndication (the data comes to you) and permalinks (which allow you to "pass it on")). He also mentioned the Rome API and called it the Hibernate of syndication.

What's the difference between RSS and Atom? I hadn't heard it put this way before. Davis called RSS "GETful" and Atom "RESTful".

He then did a live grab of a Twitter feed and identified the person in the room who had sent it.

In sum, this session was more a magic show than a talk. It made me determined to learn Groovy and how to use it with RESTful services.

The last session I attended at JavaOne 2009 was "Building Enterprise Java Technology-based Web Apps with Google Open Source Technology" by Dhanji Prasanna of Google.

Prasanna covered Google Guice, GWT (pronounced "gwit") and Web Driver, and provided a sneak preview of SiteBricks.

I'm somewhat familiar with GWT but none of the others, so my descriptions below may make no sense. It's a verbatim transcription of what Prasanna talked about.

Guice helps with testing and testability. Its advantages are:
- Simple, idiomatic AOP
- Modularity
- Separation of Concerns
- Reduction of state-aware code
- Reduction of boilerplate code

It enables applications to horizontally scale. Important precepts are:

- Type safety, leading to the ability to reason about programs
- Good citizenship (modules behave well)
- Focus on core competency
- Modularity

GWT is a Java-to-JavaScript compiler. It supports a hosted mode and a compiled mode. Core Java libraries are emulated. It's also typesafe.

The iGoogle page is an example of what look like "portlet windows", but which are independent modules that are "good citizens".

Unfortunately, social sites like OpenSocial and Google Wave have different contracts, so modules may not be portable across them.

Google Gin is Guice for GWT. It runs as Guice in hosted mode and compiles directly to JavaScript. There is no additional overhead of reflection.

Types are Java's natural currency. Guice and GWT catch errors early, facilitate broad refactorings, prevent unsafe API usage and reason better about programs. They're essential to projects with upwards of ten developers, because these features are impossible with raw JavaScript.

Web Driver is an alternative to the Selenium acceptance testing tool, and apparently the codebases are now merging. Web Driver has a simpler blocking API that is pure Java. It uses a browser plugin instead of JavaScript, features fast DOM interaction and a flexible API and supports native keyboard and mouse emulation. Web Driver supports clustering.

Then Prasanna provided a preview of SiteBricks, which is a RESTful web framework. The focus is on HTTP and lessons have been learned from JAX-RS. There are statically typed templates with rigorous error checking. It's concise and uses type infererence algorithms. It's also fast and raises compilation errors if anything is wrong.

SiteBricks modules are Guice servlet modules. One can ship any module as a widget library. Any page is injectable. It supports the standard web scopes (request, session) and also a "conversation" scope.

SiteBricks has planned Comet ("reverse Ajax") support. The preview release is available on Google Code Blog.

That concludes my notes on JavaOne 2009. Admittedly, a lot of this has been mindless regurgitation in the interests of reporting. If these make sense to readers (even if they make no sense to me), well and good.

In the days to come, I'll ruminate on what I've learned and post my thoughts.

1 comment:

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