Patches to prevent to prevent classloader jar, etc.

I have come across several trojans using the loophole in the java/windows combo to install themselves. They are easy enough to get rid of but I can't seem to correct the problem that lets them in in the first place. Both windows xp pro and java have been updated but the trojans (classloader, archive, etc.) keep getting through.

Also, some info on exactly how these work would be appreciated. I catch them in the java cache as an idx file and a jar file. What is the trip that extracts them ? Basic explanations appreciated.

Thx

That is because your defences are pro, active.
That means letting them in, befor detection.

Software, like, Spyware blaster,etc. Stops the infection at source but is still pro active. This is because it relies on, definitions, that are already identified as harmfull.

Fair enough. I run spybot, adware se, avg and zone alarm. I know the trojans will be detected eventually but I have learned to look for them before these are needed, and before they extract themselves (which is when they seem to be detected) and require more detailed removal. Is there not a way to patch the hole they use to get in ? It must be a fairly common problem. Anything I read suggests updating windows and java but this hasn't worked.

This is as much out of interest as anything. If there is not a way to fix it, I would appreciate some info on how they get there and activate themselves.