The java generation for type `(string|Null)[]` was creating `@return one of <code>List<String></code> or <code>ElementList<Null></code>`
see example:
```
@SuppressWarnings({"WeakerAccess", "unused"})
public class UriList extends Response {
public UriList(JsonObject json) {
super(json);
}
/**
* A list of URIs.
*
* @return one of <code>List<String></code> or <code>ElementList<Null></code>
*/
public Object getUris() {
final JsonObject elem = (JsonObject)json.get("uris");
if (elem == null) return null;
if (elem.get("type").getAsString().equals("String")) return new String(elem);
if (elem.get("type").getAsString().equals("Null")) return new Null(elem);
return null;
}
```
My change is the simplest thing I could think of, just making the return type `List<String>` instead and allowing some of the elements to be null. But I'm happy to implement something else if someone has a suggestion for a better type (along with how to get the generate code to produce it)
Closes https://github.com/dart-lang/sdk/pull/48309https://github.com/dart-lang/sdk/pull/48309
TEST=N/A
GitOrigin-RevId: fa9dddad68219e697998c4a011a82d6860f44bfb
Change-Id: I79cf2aedf0672354a2fd28c8962740f6fcea4f4c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/231740
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Ben Konyi <bkonyi@google.com>
Helin Shiah