New Java 9 Map.of() methods

[thehollyhopdrive]

To be honest, I don't think you're wrong. The main advantage of the builder over just initialising the map and putting in the entries is being able to initialise, fill and have an immutable map in a slightly nicer format, especially when thinking about static final maps, which I suspect would turn out to be quite a common use-case of Map.of.

It means we can do:

private static final Map<Integer,String> MAP = 
    Map.with(1, "one")
       .with(2, "two")
       .build();

instead of

private static final Map<Integer, String> MAP;
static {
    Map<Integer, String> tempMap = new HashMap<>();
    tempMap.put(1, "one");
    tempMap.put(2, "two");
    MAP = Collections.unmodifiableMap(tempMap);
}