What's a "nested top-level class"? Perhaps you are wanting to load an inner class. If so, you can do so with Class.forName(), but you must separate the outer class name from the inner class using a dollar-sign, not a dot.
For example, if Inner is an inner class defined in class org.pete.Outer, you can load it with Class.forName("org.pete.Outer$Inner").
Betty Rubble? Well, I would go with Betty... but I'd be thinking of Wilma.
That's the term Sun originally used to describe a static member class (according to the badly-named "Inner Classes Specification"). It was a very confusing choice, and fortunately Sun did away with the term when the Java Language Sepcification 2nd edition came out. (Top-level and nested are now mutually exclusive, as they should be based on what they mean in English.) They didn't really announce this change, but just did it. So you will still occasionally encounter books and people using the old term.
[Peter]: Perhaps you are wanting to load an inner class.
Actually it's a nested class, but not an inner class. The solution of using $ as the separator still applies though. Documented here. [ November 08, 2005: Message edited by: Jim Yingst ]