Room An a SQLite object mapping library. Use it to easily convert SQLite table data to Java objects and avoid boilerplate code.
Room is an object-mapping library that provides local data persistence with minimal boilerplate code by abstracting away some of the underlying implementation details of working with raw SQLite tables and queries. It also allows you to observe changes to the database's data, including collections and join queries, exposing such changes using LiveData objects. It even explicitly defines execution constraints that address common threading issues, such as accessing storage on the main thread.
At compile time, it validates each query against your data schema, so broken SQL queries result in compile-time errors instead of runtime failures.
Room can return RxJava, Flowable and LiveData observables.
If your app already uses another persistence solution, such as a SQLite object-relational mapping (ORM), you don't need to replace your existing solution with Room. However, if you're writing a new app or refactoring an existing app - because Room takes care of these concerns for you - we highly recommend using Room to persist your app's data.