My goal is to serialize a class implementing the Collection interface as JSON object instead of a JSON array. The following class is a simplyfied example:

```
public class CollectionImplementation implements Collection<String> {
  private final List<String> _wrappedList = new LinkedList<>();
  private String _otherField = "asdf";

  @Override
  public boolean add(String e) {
    return _wrappedList.add(e);
  }

  @Override
  ...
}

```

The result of `new Gson().toJson(collectionImplementationInstance)` is:

```
["str1","str2",...]

```

which misses the other field. Instead, I would like to get:

```
{"_wrappedList":["str1","str2"],"_otherField":"asdf"}

```

Is there a way without manually adding all fields to the JSON?