Yes and: toString() and clone(). Further: default implementations should be synthesized by the runtime. Prevents subtle bugs when the equals(...) and hashCode(

Yes and: toString() and clone(). Further: default implementations should be synthesized by the runtime. Prevents subtle bugs when the equals(...) and hashCode() implementations are incorrect or missing. eg contract for HashMap. To backfill, perhaps Object could extend new base class NakedObject, and implement your new interfaces Equalable, Hashable. Then classes which don't need identity can extend NakedObject. Maybe the "canonical Object" was motivated by prior experience with Self or some such. It definitely calmed down people new to Java & OOP. I think it was the right call at the time.