Unexpected NullPointerException When Using Room with Coroutine in Android 14
Can someone help me understand I've searched everywhere and can't find a clear answer... I'm stuck trying to Could someone explain I'm working on a personal project and I'm working with a `NullPointerException` when trying to retrieve data from my Room database using Kotlin Coroutines in my Android app targeting API level 34. The behavior occurs intermittently when the `getUserById` function is called within a `viewModelScope.launch` block. Here's the relevant code snippet: ```kotlin class UserViewModel(private val userDao: UserDao) : ViewModel() { fun getUserById(userId: Long) { viewModelScope.launch { val user = userDao.getUserById(userId) // Potential NullPointerException occurs here // Do something with user } } } ``` The DAO method is defined like this: ```kotlin @Dao interface UserDao { @Query("SELECT * FROM users WHERE id = :userId LIMIT 1") suspend fun getUserById(userId: Long): User? } ``` I have verified that the userId being passed is valid, yet sometimes `user` ends up being null, which results in a `NullPointerException` when I try to access its properties. I've tried checking for null before using it, but the scenario still continues. I also have the following Room setup in my `Database` class: ```kotlin @Database(entities = [User::class], version = 1) abstract class AppDatabase : RoomDatabase() { abstract fun userDao(): UserDao } ``` I ensure that the database is initialized before making any calls: ```kotlin val db = Room.databaseBuilder( context, AppDatabase::class.java, "user_database" ).build() ``` I've run tests to query users outside the coroutine scope and they return as expected. Could this be a threading scenario, or am I missing something in my Coroutine setup? Any insights would be greatly appreciated! This is part of a larger desktop app I'm building. Has anyone else encountered this? I'm working with Kotlin in a Docker container on Ubuntu 20.04. Has anyone else encountered this? I recently upgraded to Kotlin 3.10. Is there a simpler solution I'm overlooking?