This paper promotes the use of a mathematical concept lattice based upon the binary relation of accesses between methods and fields as a novel visualization of individual JAVA classes. We demonstrate in a detailed reallife case study that such a lattice is valuable for reverseengineering purposes, in that it helps reason about the interface and structure of the class and find errors in the absence of source code. Our technique can also serve as a heuristic for automatic feature categorization, enabling it to assist efforts of re-documentation.