Native Java JDK vs. Linux Java JDK via emulation

[Tabor Kelly]

Hello Again,

First of all, I checked (http://www.freebsd.org/java/), but it did not 
have the info I was looking for (it also didn't seem to have any contact 
info for their authors).

So, my question:

What is the difference between the Native Java JDK (java/jdk14), and the 
linux one (java/linux-sun-jdk14), besides the obvious fact that 
java/linux-sun-jdk14 is officially sanctioned by Sun?

Also, if java/jdk14 is a native binary build of Java, why does it 
require java/linux-sun-jdk14?

Finally, a more general question: why do ports require specific versions 
of java? For example: The OpenOffice port requires java/jdk-1.4.2p6_7, 
shouldn't any vendor's copy of version 1.4 of the JDK work?

Thank You,

Tabor Kelly