Facebook-graphics-api-android

I am trying to request multiple fields from api chart.

Using the code below overwrites previous values.

params.putString("fields", "id");
params.putString("fields", "email");
params.putString("fields", "picture");
params.putString("fields", "birthday");

JSONObject json = new JSONObject(mFacebook.request("me",params));

However, when I use

params.putStringArray("fields", new String[]{"id", "email", "picture", "birthday"});

gives:

Bundle[{fields=[Ljava.lang.String;@44a04bb8}]

Has anyone encountered this issue?

Thanks in advance.