Greg Vaughn's Blog

J2EE Archives

JavaSpaces Still Alive

I've long watched the JavaSpaces and Jini community because it is such a great technology, but sadly from a work experience standpoint, I haven't had a chance to really get my hands dirty. That's still the case, but I have new hope. JPower has released a free (as in beer) JavaSpace JMX component. It runs in any JMX container. It offers hot deployable JavaSpaces, backed by persistent storage via JDBC, and optional security via SSL. Coming in the next release is a Jini services container.

This is a really great (and subversive) idea. I wish I'd thought of it. I'm noticing a lot of work down below the level of J2EE. In some sense, it seems that J2EE has been developed backwards. Servlets came along first which is at the presentation layer, later EJB's came along for business logic. Next came CMP Entity Beans warts and all. Now JDO seems to be taking over the mindshare for persistence. However, the lower layers of infrastructure came later, or at least showed up with very little visibility. JNDI is an important layer that showed up with EJBs. Later came JMX, and then app server vendors worked furiously to build the foundations of their products on JMX. That's where the real low level foundation exists today. Aspect Oriented techniques (or Interceptor oriented if you prefer) are being using to more modularly implement much of these underpinnings.I also hear that Jini is even being used in some places for clustering of the app servers.

The subversive part (and I use that in the fondest sense) is now using JMX to get JavaSpaces and Jini in the picture as peers of the JMX managed web and EJB containers. JPower is the first I've heard of this, but I'll bet it won't take long for other vendors to do the same. Later on Sun might even catch up and make them part of the J2EE spec.

I'm excited that this might be the first step taking JavaSpaces and Jini to the mainstream. Go JPower!

How to Become a Java Guru

I'm probably preaching to the choir here, but hear me out just in case. I'm not speaking from the position of having already achieved guru status, but I think I've got a handle on the path to get there. Correct me if I'm wrong.

Find some giants, and stand on their shoulders, to co-opt Isaac Newton's famous quote. I don't mean this as a way of keeping someone else down, but instead building upon their insight and work. Become aware of what's offered in the Java libraries you work with, be it J2EE, J2SE, or J2ME. There's lots of good stuff in there that often gets overlooked. Case in point: the other day I was doing a methodology exercise of breaking a feature into individual tasks. The feature was logging into a J2EE application. Out of about six groups particpating in the exercise, mine was the only one that had a tasks of learning the basics of JAAS (Java Authentication and Authorization Service) and configuring it in the appserver. All the other groups were ready to write their own custom login logic. I've never used JAAS before, but I've read an overview and knew it was commonly supported in J2EE containers (It's actually now part of J2SE 1.4.) and was specifically intended to be a reusable login service.

Now, the first time learning and using a new API may not save you any time over a scratch custom implementation, but it will save time the second and subsequent times you need to use it. Think over the long term about all these APIs you've had some experience with and how much faster you can do the well known pieces of your application. That frees up more time to work on the truly unique aspects of the particular application. Not only that, but coworkers will notice your experience and start coming to you for advice and you'll be able to help the speed of your entire team.

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