[CentOS] help with alternatives

I've installed java-1.6.0-openjdk (from EPEL) on a CentOS 5.2 x86_64  
system and see that it has not registered itself with alternatives.

First, is there a reason I should know about that it does not set  
itself up as an alternative?

But second, if I was to configure it myself, the syntax is

alternatives --install link name path priority    ... and other  
optional stuff


Looking at other examples, I'm not clear on the difference between  
link and path in this command

Thanks,
Tony Schreiner
Boston College