Learning java - any advice please?

I've finally decided it's time I learnt java. I want to be able to write
client applications in java which interact with the AS/400.

However, I'm confused and unsure where to start.

First question. What software do I need to obtain and install on my PC to do
this? I thought I wanted VisualAge for Java, but it appears the goalposts
have moved and it's now some flavor of Websphere I need. Can anyone tell me
precisely what flavor? I want to develop under Windows - learning Linux at
the same time doesn't sound like my idea of fun. And I think I need the
equivalent of what used to be called the "Enterprise Toolkit for AS/400".
What do I ask for to get the iSeries bits?

Second question. Where do I get this software from? Can I buy it online?
You'll probably say "yes", but wait a minute - I'm in the UK and I can't
find anything that looks remotely like what I want on the IBM UK online
sales site. And the website appears to be down at the moment in any case.

Third question. If IBM are so eager for grey-haired old RPG-ers like me to
switch on to this brave new world of java, why do they make it so
complicated?!

Any help gratefully received by a poor decripit S/38 guy who's almost ready
to give up before he's even started!

Pete