Is it safe to assume that if you have two different jdk's installed (thanks to Oracle) that when you issue a command such as: java -version at the DOS prompt, that the first jdk referenced in the classpath will be the one which is used? Oracle installed jdk 1.3.1 at the beginning of my classpath variable and this is why I'm assuming I get 1.3.1 when I issue java -version Which by the way the jdk 1.3.1 doesn't even show up in my control panel under Add/Remove programs. What's up with that?
java -version will run whichever is first in your PATH, not your CLASSPATH -- the latter will be used by whichever JDK Windows chooses to execute, but it's up to Windows to choose one (and it will use PATH to do so.) Regarding the add/remove: it's perfectly possible to simply copy the JDK files onto a computer where they'll work fine, without having made any registry entries, so they won't show up in add/remove.