Like half the rest of the programming universe, I downloaded Eclipse Europa yesterday to update my development environment with the latest and greatest released version of the Eclipse IDE. I spent a few moments figuring out what kind of developer I was given the choices offered. Since I develop OSGi code, I figured RCP/Plug-in developer was the best choice to start with. It would have been nice if OSGi bundle development was mentioned somewhere in there :-)
In any case, the "installation" (unzip is my favorite installer!) went fine. Since I deal with a few XML files, I like WST for the XML editors, etc. it provides. However, when I started Eclipse, even though WST is included in the RCP/Plug-in developer download, none of the WST stuff was functional! After some time trying to figure out what was up, I eventually figured out that it was because the default JRE on my system is 1.4! (Yes, I know it is rather retro, but I still use it as the default. I have Java 5 installed which I use when I need it.) WST just silently does not work when you start Eclipse with 1.4. No warnings or errors in the log view. I guess the WST bundles simply don't resolve because they probably require the Java 5 execution environment. Starting Eclipse with Java 5 solved the problem (and even opened the Welcome screen which I realized did not show up when I started with 1.4!).
I eventually found the Eclipse JRE page which states that the Java EE developer version requires Java 5 but I picked the RCP developer version. And while the RCP version started on 1.4, some significant function was not operational. Perhaps the website should just state that Java 5 is required for all downloads or provide some warning to the user that on Java 1.4 functions X, Y and Z don't work in Eclipse 3.3.