My code snippet for nested json object:
JsonArray arr = jsonObject.getAsJsonArray("data");
for(int i = 0; i < arr.size(); i++) {
String _Id = arr.get(i).getAsJsonObject().get("_id").getAsString();
String Name = arr.get(i).getAsJsonObject().get("name").getAsString();
int Trips = arr.get(i).getAsJsonObject().get("trips").getAsInt();
}