AppDatabase.java

package dao;

import android.content.Context;

import androidx.room.Database;
import androidx.room.Room;
import androidx.room.RoomDatabase;

@Database(entities = {Student.class},version = 1, exportSchema = false)
public abstract class AppDatabase extends RoomDatabase {

    private static final String DATABASE_NAME="student_db";
    private static final Object LOCK=new Object();
    private static AppDatabase instance;
    public static AppDatabase getInstance(Context context){
            if (instance==null){
                synchronized (LOCK) {
                    instance = Room.databaseBuilder(
                            context.getApplicationContext(),
                            AppDatabase.class,
                            AppDatabase.DATABASE_NAME).build();
                }
            }
            return instance;
    }
    public abstract StudentDAO getStudentDao();
}