This is the design document of my implementation of Gitlet, a version-control system that mimics some of the basic features of the popular system Git. It passed all tests on the gradescope autograder provided by University of California Berkeley, CS 61B. Source code is available upon request.

Subtype polymorphism (providing a single interface to entities of different types) and dynamic type selection (DMS) might be one of the most obscure part for Java beginners like me. Here I am trying to write an article on this topic gathering my solutions and approaches to problems in such topic.