Every Java project is designed for reusability. Yet when time comes to do a new project in the same domain we always opt for building from scratch. Is software reusability, especially in the J2EE realm, just a myth?

Some developers are easily test-infected - they take to unit testing like a duck to water. Others need some time and encouragement, but eventually "get it". A third group appears to have immunity to test infection. I invent a test-gene model to categorize these groups and look at its implications for the future of developer/unit testing.

In his RailConf keynote, Rails creator David Heinemeier Hansson explained his reasoning for preferring numeric entity IDs in URLs as opposed strings. What's your opinion?

Software is become an increasingly important consumer of Web content. When software and humans are both intended targets of a Web-accessible resource, should you provide separate URLs for that resource based on a client's preferred content type, or a single URL and rely on server-based content negotiation to serve up the appropriate content?

An indoor water park, in Ohio, in the middle of the winter sounded like a very strange destination. But the conference turned out to be very diverse and stimulating, and I was able to try out version two of my new presentation, "The World is Dynamic."

Java's checked exceptions sometimes force you to catch a checked exception that you believe will never be thrown. Best practice dictates that you wrap that in an unchecked exception and rethrow it, just in case. What exception class do you wrap with in that case?

Interface implementations are not just found using factories. You can use compile or link time alterable implementations.

Early bird registration ends January 15.

What I'll be doing at PyCon 2007 ("Idiomatic Python" tutorial, Docutils sprint), and a reminder of the early-bird registration deadline.

Everything I'm doing seems to be about small chunks of thought. These chunks need tracking, comparing, versions controlling and melding into presentations of varying narrative richness. The interesting projects and interested parties include software engineers, publishers and academics but there's no killer app in sight?

In which Andy suffers an extreme bout of cynical disbelief in the merits of Resource Oriented Architecture and "solving" the discovery problem by giving up and just having a description as part of a "Resource".

At SD Forum 2006, two eBay architects presented an overview how eBay's architecture handles a billion page requests a day, and how that architecture evolved from a few Perl scripts to 15,000 application instances running in eight data centers. One conclusion from the presentation is that scaling is only in part a question of architecture.

This edition of my occasionally-published newsletter, which also goes out by email, covers upcoming events and the status of various projects.

The REST architecture style includes several points of interest. One of them is a "uniform" or "fixed" API. There is a subtle issue with that. I don't really think that this concept is what REST is all about.

How do you develop a Roadmap for a broad-ranging community, encompassing several service-oriented architectures? Here are some ideas.