Room Persistence Library run time exception when calling Rooms inMemoryBuilder method

Question

When following the tutorial for setting up the Room persistence library I run in to this error when testing on an Android device.

java.lang.RuntimeException: cannot find implementation for PackageName.AppDatabase. AppDatabase_Impl does not exist

I know a similar question has been asked however the issues were due to kotlin gradle issues. Possible Duplicate

Test class:

@RunWith(AndroidJUnit4.class)
public class LocalDatabaseTest {

    private PhotoDao mPhotoDao;
    private AppDatabase mDb;

    @Before
    public void createDb() {
        Context context = InstrumentationRegistry.getTargetContext();
        mDb = Room.inMemoryDatabaseBuilder(context.getApplicationContext(), AppDatabase.class).build();
        mPhotoDao = mDb.photoDao();
    }

    @After
    public void closeDb() throws IOException {
    //mDb.close();
}

    @Test
    public void testPreConditions() {
        assertNotNull(mDb);
   }

Dao:

    @Dao
    public interface PhotoDao {
    @Delete()
    public void delete(Photo... photos);

    @Update
    public void update(Photo ... photos);

    @Insert
    public void insert(Photo ... photos);
    }

Database:

@Database(entities = {Photo.class}, version = 1)
public abstract class AppDatabase extends RoomDatabase {
public abstract PhotoDao photoDao();
}

Stack Trace:

java.lang.RuntimeException: cannot find implementation for *PackageName*.AppDatabase. AppDatabase_Impl does not exist
at android.arch.persistence.room.Room.getGeneratedImplementation(Room.java:90)
at android.arch.persistence.room.RoomDatabase$Builder.build(RoomDatabase.java:340)
at pics.chooz.choozpics.LocalDatabaseTest.createDb(LocalDatabaseTest.java:40)
at android.support.test.internal.runner.TestExecutor.execute(TestExecutor.java:59)
at android.support.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:262)
at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1853)

Gradle:

apply plugin: "com.android.application"
apply plugin: "android-apt"

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.2"

    defaultConfig {
        applicationId "*Package Name*"
        minSdkVersion 16
        targetSdkVersion 25
        versionCode 50
        versionName "1.0.32"
        multiDexEnabled true
        testInstrumentationRunner     "android.support.test.runner.AndroidJUnitRunner"
}

dexOptions {
    javaMaxHeapSize "4g"
}

buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile("proguard-android.txt"), "proguard-rules.pro"
    }
    debug {
        debuggable true
    }
}

lintOptions {
    abortOnError false
    disable "ResourceType"
}

sourceCompatibility = 1.7
targetCompatibility = 1.7
compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_7
    targetCompatibility JavaVersion.VERSION_1_7
}

packagingOptions {
    exclude 'META-INF/ASL2.0'
    exclude 'META-INF/LICENSE'
    exclude 'META-INF/NOTICE'
}
}
dependencies {

androidTestCompile "com.android.support:support-annotations:$androidVersion"
androidTestCompile 'com.android.support.test:runner:0.5'
androidTestCompile 'com.android.support.test:rules:0.5'

    compile "android.arch.persistence.room:runtime:1.0.0-alpha1"
    annotationProcessor "android.arch.persistence.room:compiler:1.0.0-alpha1"
}

Answer 1

I changed the 'annotationProcessor' keyword to 'kapt' in my gradle file. Like so:

kapt "android.arch.persistence.room:compiler:1.0.0"

Answer 2

Rule of thumb when using Kotlin:

Replace your annotationProcessor dependencies with kapt. Also, include apply plugin: 'kotlin-kapt' in your app's build.gradle.

Answer 3

Have a look on this thread

The solution is to replace :

annotationProcessor "android.arch.persistence.room:compiler:VERSION"

with :

kapt "android.arch.persistence.room:compiler:VERSION"

Answer 4

You must add the annotation processor dependency to the module where your AppDatabase is. I assumed that the app would take the depencency from my API library module, where my data model classes are, but apparently this is not the case.

Answer came from this google issue: https://issuetracker.google.com/issues/67520422 And this SO answer: https://stackoverflow.com/a/43918701/1959110

Answer 5

Had the same issue with

• gradle 3.2.0-alpha09
• koltin 1.2.31

Due the removal of apply plugin: 'kotlin-kapt' and other buggy stuff.. I had to downgrade to kotlin 1.1.60 to make it work. Then use:

apply plugin: 'kotlin-kapt'

dependencies {
    ...
    implementation 'android.arch.persistence.room:runtime:1.0.0'
    kapt "android.arch.persistence.room:compiler:1.0.0"
}

an other option would be to write the DB entities/DAOs and DataBase in Java instead.

Answer 6

In my case I have change scheme but forgot to change version number.

@Database(entities = {Task1.class, Task2.class}, version = 2)

Answer 7

For kotlin

 //Room
implementation "android.arch.persistence.room:runtime:1.0.0"
//Room annotation processor
kapt "android.arch.persistence.room:compiler:1.0.0"

apply plugin: 'kotlin-kapt'

Answer 8

change the annotationProcessor from annotationProcessor 'android.arch.persistence.room:runtime:1.1.0' to annotationProcessor 'android.arch.persistence.room:compiler:1.1.0'