let Obj = [
[
{o:'-12188866'},
{o:'-175'},
],
[
{g:78554274,t:30718264},
]
];
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.reflect.TypeToken;
import java.lang.reflect.Type;
import java.util.*;
String json = "[[{o:'-12188866'},{o:'-175'}],[{g:78554274,t:30718264}]]";
Type listType = new TypeToken<List<List<Map<String, String>>>>(){}.getType();
Gson gson = new GsonBuilder().create();
List<List<Map<String, String>>> list = gson.fromJson(json, listType);