[pjmlp]

Last time I checked, Object was a type.

But if you prefer, advance a few years up to 2004 (1.5), still 5 years before Go was created.

Also HashMap is just one implementation among all of those that are available in the standard library for the Map interface, each one tailored for a specific use case, with regard to performance and memory constraints.

In Go you cannot change the behaviour of that built in hash map.