Software development is just too complex these days for anyone to really know what they are doing in more than one 'programming world', according to Joel.

I think that he's probably right. I'm painfully climbing the foothills of the Java/J2EE world at the moment.

The iSeries world, my bread and butter for many a year, is probably static enough these days that I don't need to get left behind. This is good - it took a long time before I knew how to make the '400 fly in the first place.

A number of people at work are getting into the .NET world at the moment, in their own time. This seems a little odd to me - there is no realistic prospect of anyone making use of this stuff in my company in the near future. Still, I can see the attraction - .NET might not kill J2EE, but MS won't let .NET die under any circumstances.

Not that I'm tempted, you understand - MS are the Great Satan, so far as I am concerned. No, I'll stick with Java/J2EE.

Some tools are just so good that they help you whatever world you are in.