My app database class
@Database(entities = {Detail.class}, version = Constant.DATABASE_VERSION)
public abstract class AppDatabase extends RoomDatabase {
            
        
Use the following gradle link:
compile 'android.arch.persistence.room:runtime:1.0.0-alpha9'
annotationProcessor 'android.arch.persistence.room:compiler:1.0.0-alpha9'
You need to create diffretn singloton class and get the Appdatabase from ther like this:
RoomDB.java
public class RoomDB {
private static RoomDB INSTANCE;
public static AppDatabase getInstance(Context context) {
    if (INSTANCE == null) {
        INSTANCE =
                Room.databaseBuilder(context.getApplicationContext(), AppDatabase.class, Constant.DATABASE).allowMainThreadQueries().build();
                //Room.inMemoryDatabaseBuilder(context.getApplicationContext(),AppDatabase.class).allowMainThreadQueries().build();
    }
    return INSTANCE;
}
public static void destroyInstance() {
    INSTANCE = null;
}
App.java
public class App extends Application {
private boolean appRunning = false;
@Override
public void onCreate() {
    super.onCreate();
    RoomDB.getInstance(this); //This will provide AppDatabase Instance
}