XML documents typically refer to external entities, for example the public and/or system ID for the Document Type Definition. These external relationships are expressed using URIs, typically as URLs.
However, if they're absolute URLs, they only work when your network can reach them. Relying on remote resources makes XML processing susceptible to both planned and unplanned network downtime.
Test-driven development (described on Wikipedia) is now widely accepted as the preferred way to develop software, especially Java software. I'm an enthusiastic supporter of this predilection - but there is a problem people seem often to overlook. I call it the Four Horsemen (also on Wikipedia) because there are four potentially major dynamic problems unreachable by testing alone.
I've always been one of those perhaps slightly annoying people who don't easily accept propositions that seem overly intricate. It's not that I'm a stroppy person - I'm pretty relaxed really - I just don't like wastefulness, and that can mean I'm unhappy when I see other people wasting their time doing things the hard way.
I wrote about the Spring Framework Mission Statement earlier. This article follows it by examining the second Spring mission statement bullet, which concerns the use of interfaces in Java:
Everyone knows this is a Good Thing - but why is it good?
