Some of it wasn't possible earlier or, at the very least, wasn't simple earlier. To do any kind of work on json, we need to, well, have any json value. This means we need some constructors. Of course, ...

which it interprets as an object with two keys, one that is the string a and one that is the string [{"b":2}]. Strict JSON, of course, only accepts string literals as keys in objects. JSON-java is ...