The command below is used to run and store the 'Materia' obtained by the java.reflect.Reflect mechanism of self-reflection. 'Materia' means, a listing of the Constructors, the Fields or variables, & the Methods    of the particular Java 2 class that is being Reflect-ed upon...
- The command is:
          Materia Classname groupname

...where 'Classname' is the name of the Java class to get Materia on, and 'groupname' is the name of the package that that Class is in. 'Classname' is case-sensitive, but the 'groupname' is usually or always in lower-case.
For example, for the class Label in Java's AWT, the proper command is
          Materia Label awt

...because that class is, in full package specification: java.awt.Label

...of course, these listings are not ideally helpful as to details, and you may need a manual just to construct the Class that you are using Reflect to extract all this info from - that is, the exact constructor parameters are not always obvious, if a default 'ClassConstructor()' is not present in the particular class being examined.
                - Good Luck! and keep a good manual handy too. To help with the constructors, you might take a glance in the good Java 2 basic but very comprehensive reference guide, "The Java Developers Almanac" by Patrick Chan... see link below, if this is a web page (& if not, remind me <> to publish one! ;)

[-R. Hess, August 30 & September 27, 2001.]