I don't like this:

    String body = ... REST response body, which is a JSON document ... ;
    JsonValue json = Json.parse(body);
    json.get("properties").get("periods").asList().stream()
        .mapToInt(j -> j.get("temperature").asInt())
        .average()
        .ifPresent(IO::println);

Why am I able to call `.get(string)` or `.get(int)` on a JsonValue? Shouldn't these be on the JsonObject and JsonArray instead?

> If the JsonValue instance is of the wrong type, or if the requested member or element does not exist, the access methods throw a JsonValueException.

So if I get an exception, I can't tell whether the value was of the wrong type or the object didn't have the requested key? This looks like a footgun to me.

They just brought pattern matching to Java. Why not move those .get to JsonArray and JsonObject? That would solve this confusions. So we could just use something like `if (json instanceof JsonObject o) o.get("properties")`