May 29th, 2007
Canoo’s Janak Mulani is speaking on the following two Rich Internet Application topics at JAX India:
Rich Internet Applications and AJAX – Selecting the Best Product
Thursday, May 31 at 10:20 am
Java Rich Internet Application (RIA) Patterns
Thursday, May 31 at 1:30 pm
May 29th, 2007
There was a presentation by Nikolaos Kaintantzis of Zühlke at SET 2007 in Zürich that discussed various web technologies for Rich Internet Application development.
Canoo’s UltraLightClient was part of the technologies discussed.
Here are the slides (in German):
Smarte Technologien für Web-Clients – Orientierungshilfe im Java-Client-Dschungel.
May 15th, 2007
Hans-Dirk Walter and Patrick Lisser will be presenting at this year’s Orbit / iEX 07 in Zürich:
RIA und AJAX – Ein Wegweiser durch den Dschungel (in German)
on Tuesday, May 22, at 15:30 at Messezentrum Zürich.
This session is specially suited for IT managers and architects interested in using Rich Internet Application technologies.
May 13th, 2007
Now for the final stretch of this year’s JavaOne conference: the pavilion closed on Thursday and we dismantled the booth pretty quickly. After half an hour everything was packed and we took our equipment back to the hotel. Hence, today I could really enjoy the conference without any booth duties.
“Comparing the Developer Experience of Java EE 5.0, Ruby on Rails, and Grails” looked really promising to me. I know Java EE from real programming practice, Rails and Grails just from reading some articles. The speaker, Thomas Daily, had a funny Australian accent and made quite a good show. He demonstrated how easy it is to create a simple CRUD application with all three technologies. For Java EE he had to use heavy machinery (i.e. NetBeans), though. He then presented some performance benchmarks which claimed that Java EE scales way better. The runner-up was Grails, followed by Rails. Tom Daily was somewhat biased towards Java EE (he doesn’t work for Sun for no reason), although his final recommendation was to use the tool that best fits the application. What I missed in this talk was some statements about maintainability. I would have liked to see how each of these environments coped with new requirements.
Hard core stuff was up next with “Cranking up Java Application Performance with DTrace“. DTrace allows to run instrumented code with zero impact on performance. At run time you can activate/deactivate probes in a live system. Right now, DTrace is only available on Solaris 10, but it will be available on at least one other operating system later this year. The Java VM is also instrumented, which allows to use DTrace at run-time for Java applications as well (Java 5 and newer). For Java 7 it is even planned to allow for statically adding probes to the application code. DTrace can produce a vast amount of tracing data in almost no time but the DTrace language helps to filter and aggregate this data. DTrace solves the developer’s dilemma: adding tracing statements is necessary for systemic analysis but even when switched off it usually has some impact on performance.
Java Champion Adam Bien gave a talk on “Java 6 Platform, Java DB, Swing, JNLP, Java Persistence API: The New Operating for Rich Internet Applications“. He covered a lot of ground in one hour and proved to be one of the überarchitects. Adam Bien strongly recommended to use business objects (i.e. real objects with state and behaviour) rather than SOA with dumb objects such as DTOs. The Java 6 platform and JPA make it even possible to run these business objects either on the server-side in an EJB container or on the client side outside of a container. However, I missed two topics. First, he talked a lot about the thin client challenge by which he did not mean real thin clients (i.e. presentation logic is on the server-side) but “thin clients” with just the presentation logic running on the client side. Some of these challenges do not come up with server-side presentation logic. Secondly, he should have at least mentioned approaches how to synchronize client-side database changes back to the server. Nevertheless, get hold of the slides and dive into this wealth of information.
I closed JavaOne 2007 with Neil Gafter’s “Closures for the Java Programming Language“. Neil Gafter is a brilliant speaker: perfect pace, well pronounced, deeply reflected – it’s just a pleasure to listen to him. He started with a number of cases where anonymous classes are not sufficient and argued how closures would help. Some of the code examples reminded me of my code and how I had to work around the limitations of anonymous classes. I used to develop in Smalltalk for quite some time and blocks are as natural as recursion (quoting Neil Gafter). He also argued how the Java API could be improved with closures. However, I am still undecided whether the Java language should be extended with closures. What once was a fairly small and clean language is gradually turning into a dreadnought. Java should have offered closures from the very beginning; adding it as an afterthought might have too much negative impact.
May 13th, 2007
I don’t get much sleep during JavaOne. Days are long even if you don’t attend any late night BOFs and the jetlag gets me out of bed pretty early. On the third day I start get feeling the lack of sleep and I am not too unhappy that JavaOne lasts only four days rather than five as in previous years.
My first session in the morning was “Java Persistence API: Portability Do’s and Don’ts”. I have been using Solarmetric Kodo (now with BEA) for some years and although I am not using the latest version I am still quite pleased with the functionality. The latest version of Kodo also supports JPA and therefore I was curious how JPA can be used with portability in mind. Mike Keith explained how the JPA specification was specifically designed such that vendors could add specific functionality without interfering with other vendors. A developer can refer to vendor specifics both at the property and query level and it’s quite easy to support more than one vendor. It reminded me a lot of JDO which has similar capabilities. The only thing that’s missing is a portable approach for pessimistic locking.
“Designing Scalable High Performance Rich Clients: From the Trenches” was up next. Rob Ratcliffe took part in the development of a complex Swing-based application which monitors and controls a potentially large number of mobile sensors. The talk was less than convincing, his demo nice in the beginning but way too long so I left early. If somebody tries to teach to me the advantages and disadvantages of a singleton I am definitely in the wrong session.
I was looking forward to Ben Galbraith’s talk about “Debugging Swing Apps” and I wasn’t disappointed. Ben is a brilliant presenter, although he speaks incredibly fast which might be a challenge to some people in the audience. I admired the two sign language interpreters who somehow managed to keep up with his speed (they had to take turns every ten minutes). Ben explained how to use weak references for easy fixing of memory leaks and how AOP can help to identify code that leads to sluggish user interfaces. At the end he demonstrated a tool he wrote to experiment with Java 2D, e.g. trying out Java 2D calls interactively to gauge the impact of options on different platforms. To summarize, the talk was both filled with lots of useful information and entertaining. I was quite amused when Ben tried to dodge the Apple NDA while explaining some garbage collection features on Mac OS X.
The title of “Spaghetti Is Not Tasty: Architecting Full-Scale Swing Apps” was promising but did not meet my expectations. Rather than focusing on design problems of large Swing applications he spent too much time on OSGI which can solve some problems but not all of it. The only thing I took from this talk is that for large applications it is recommended to use a message bus to distribute events, which was also mentioned by Rob Ratcliffe in his talk. Wiring listeners to too many consumers does not scale and is hardly maintainable,
My last session was about “Garbage-Collection Friendly Programming“. Three garbage-collecting engineers from Sun laid out all the do’s and don’ts in Java to effectively deal with garbage collection:
- Don’t use object pools. Java’s memory management is usually way better than Java developers can implement object pools.
- Don’t use System.gc(): The garbage collector knows better when to run, you don’t have to tell it.
- Resizing arrays frequently can put more pressure on the garbage collector
- Finalize always takes two garbage collection cycles and is therefore quite inefficient. For Java 6 the garbage collection team even convinced the AWT-team to remove all finalize methods from the AWT (and therefore Swing) components. If you need something like finalize you can either use a finally clause or weak references.
- Don’t use soft references, because it is expensive for the garbage collector to reclaim objects referenced softly. Only use soft references for quick and small caches. This contradicts what Ben Galbraith said in his session when he recommended soft references for any kind of cache.
If you have a chance to grab the slides, just do it. They contain numerous hints how to write clean and efficient code with respect to memory management.
The third day was kind of a mixed experience. I learned most in the sessions about Swing Debugging and Garbage Collection. With the other two Swing sessions the JavaOne program committee made some questionable decisions.