I did get ToolTips to work for standard Java libraries. It isn't necessarily pretty, but it seems to work, albeit sometimes slowly. Here's what you got to do:
1. Get JDK (1.5 for example)
2. Unzip src.zip
3. Within your UES project, add a group (I called it "java")
4. Within this group, add the src folder from JDK (e.g., C:\Program Files\Java\jdk1.5.0_06\src)
Patiently wait for UES to parse ~4096 java files. Voila, the JDK standard libraries now are available for IntelliTips.
Caveat: appears IntelliTips is not smart about context. For example, if you have your own "print" method within your local class, it will not only pick this use this for presenting as function definition for "print(", but will also present the other 22 print functions available from the JDK.
Ideally, IntelliTips should only present those definitions that it could get to via import statements or fully qualified referencing.