Generic classes may have more than one specializable type parameter and it may be desirable to specialize one or more of the type variables while not specializing others. The result of partial specialization may be one or more additional generic classes that are further specializable on the remaining type parameters. A runtime specializer may partially specialize a generic class to produce a partially specialized class and may subsequently further specialize the partially specialized class to generate a fully specialized class. Thus, rather than performing the specialization of a generic class all at once, such as by specializing Map into Map or Map , one type parameter may be partially specialized, such as resulting in Map , and then at some later time the remaining type parameter(s) may be specialized, such as to generate Map or Map .