Portage version management breaks down for JDKs?

[clattuc]

Strictly speaking it doesn't - but in this situation it's very inconvenient, and probably not limited to Java development either.

I'll explain:
I'm a Java developer, and usually have a few different versions of the JDK installed. Not a very unusual situation on a development station.
For example, at the moment I have Blackdown's JDK 1.3, IBM's 1.1.8, IBM's 1.3.1, Sun's 1.3.1_03 and Sun's 1.4.0 installed. (And Sun's J2EE 1.3.1 as well)

Now, when I do a "emerge clean world", it tries to uninstall Sun's 1.3.1_03. Although 1.4.0 supersedes 1.3.1_03, it doesn't replace it, and portage shouldn't try to uninstall it.

Interestingly, it doesn't do this for some other ebuilds - still have to work out if that's by design, or a bug in portage.
Is there something wrong with the Sun-jdk ebuilds, or is this a more general problem in portage?