public static Map<String, String> getEntries(final String json,
                                                 final String... keys) {
        if (keys == null || keys.length == 0) {
            return Collections.emptyMap();
        } else {
            return getEntries(json, Set.of(keys));
        }
    }
Gets the entries from the passed json that are children of the root object.
Avoids having to parse the whole object if you only want to get a few keys.
Does not descend into child objects/arrays.
If the root is an array, returns an empty map.

@param json The json to parse.
@param keys The fields to find.
@return The entries with keys matching keys
stroom-util/src/main/java/stroom/util/json/JsonUtil.java