for use room data base in android you need to setup faw things first you have to add two deandancy in your gradel file implementation "android.arch.persistence.room:runtime:1.0.0-beta2" annotationProcessor "android.arch.persistence.room:compiler:1.0.0-beta2" then make a entity class and dao class in your file structure Data base class package com.plzf1.rollearn.database; import android.arch.persistence.room.Database; import android.arch.persistence.room.RoomDatabase; @Database(entities = User.class , version = 1) public abstract class MyDataBase extends RoomDatabase { public abstract UserDao userDao(); } Entity Class android.arch.persistence.room.ColumnInfo; import android.arch.persistence.room.Entity; import android.arch.persistence.room.PrimaryKey; @Entity(tableName = "user") public class User { @PrimaryKey(autoGenerate = true) private int us...