Liam Miller-Cushon has published a document simply called "Equivalence" in which he proposes "to create a library solution to help produce readable, correct, and performant implementations of equals() and hashCode()." In this post, I summarize some reasons why I believe this proposal is worth reading for most Java developers, even if the proposal never gets implemented, and why the proposal's implementation would benefit all Java developers if realized.
Miller-Cushon opens his proposal with a single-sentence paragraph: "Correctly implementing equals() and hashCode() requires too much ceremony." The proposal points out that today's powerful Java IDEs do a nice job of generating these methods, but that there is still code to be read and maintained. The proposal also mentions that "over time, these methods become a place for bugs to hide." I have been on the wrong end more than once of particularly insidious bugs caused by an error in one of these methods and these can be tricky to detect.