[EdwardDiego]

You're right that Java's Hashmap only ever resizes upwards - the most common use case. However, if there's a need to remove that memory after clearing() then the typical use case is to do something that allows the GC to sort it.

E.g.,

    var map = new HashMap<Bla, Bla>();
    // Many things added to map
    // Many but not all things removed from map
    // to shrink it to size of remaining items
    map = new HashMap<>(map);

Yeah, it's not nice, but the people who wrote the JDK are far smarter than me, so I figure they optimised for the 99% use-case, not the 1%.

[mariusor]

I think that's exactly what TFA is proposing by recreating the map

    m := make(map[Bla]Bla)
    // add to map
    // mark map as ready for GC
    m = make(map[Bla]Bla)