Note: Failed to read get kotlin metadata for [Ljava.lang.Object;@79d6c4df

Question

I keep getting this error. I am working on a project and in the middle of development, I decided to migrate to Android X.

I get the error below:

Note: Failed to read get kotlin metadata for [Ljava.lang.Object;@79d6c4df

There is the same error in a entity file and 4 of the same error in the respective DAO as well.

Here is the code of DAO:

@Dao
public interface FlockDao{
    @Query("SELECT * FROM flock_table")
    LiveData<List<Flock>> getAllFlocks();

    @Query("SELECT * FROM flock_table WHERE fid IN (:flockIds) LIMIT 1")
    Flock loadFlockById(int[] flockIds);

    @Insert
    void insert(Flock flock);

    @Update
    void update(Flock flock);

    @Delete
    void delete(Flock flock);
}

And my entity is:

@Entity
public class Flock{

    @PrimaryKey(autoGenerate = true)
    private int fid;

    @ColumnInfo(name = "user_id")
    private int uid;

    @ColumnInfo(name = "name")
    private String name;

    @ColumnInfo(name = "capacity")
    private int capacity;

    @ColumnInfo(name = "type")
    private String type;

    @ColumnInfo(name = "arrived")
    private Date arrived;

    .....rest of the code is omitted, there are constructor, setters and getters
}

Apparently Date data type is not supported by room. So that is causing the problem. — dawn, Mar 22 '19 at 04:38
Shouldn't the standard `@TypeConverter` class(es) handle the `Date` to `Long` conversion? — lukegjpotter, Apr 05 '19 at 22:47
I downgraded the dependency as said in some answers and removed the Date type field and used string instead. @RushDroid — dawn, Apr 11 '19 at 04:51

Rence Rei · Accepted Answer · 2019-04-18T21:53:32.257

32

I updated my Room depency to 2.1.0-alpha05 and got the same problem. Returning to 2.1.0-alpha04 solved mine.

implementation 'androidx.room:room-runtime:2.1.0-alpha04'
annotationProcessor 'androidx.room:room-compiler:2.1.0-alpha04'

UPDATE If you really want to use Room version 2.1.0-alpha05, add the following depency to your project repository:

maven { url 'https://kotlin.bintray.com/kotlinx/' }

Reference: AndroidX Room Release Notes

UPDATE I tried 2.1.0-alpha06.

implementation 'androidx.room:room-runtime:2.1.0-alpha06'
annotationProcessor 'androidx.room:room-compiler:2.1.0-alpha06'

Then I add the depency to my project repository,

maven { url 'https://kotlin.bintray.com/kotlinx/' }

There was na error but it compiled. I tested my app in real device for weeks and there wasn’t any issue running my app. My Room database is working fine.

edited Apr 18 '19 at 21:53

answered Mar 18 '19 at 22:07

Rence Rei

473
3
9

1

I am using 2.1.0-alpha05 and I have setup maven url properly. I will try using 2.1.0-alpha04. Thanks for your reply. – dawn Mar 19 '19 at 10:37
3

Still couldn't make work alpha05 neither alpha06. Downgrading to alpha04 works! – Kostanos Mar 29 '19 at 17:11
It worked! I think no need to add this for alpha04. maven { url 'https://kotlin.bintray.com/kotlinx/' } – Waheed Nazir Apr 03 '19 at 12:44
2

doesn't make any difference even after adding maven { url 'https://kotlin.bintray.com/kotlinx/' } – Sachithd Apr 10 '19 at 07:09

score 9 · Answer 2 · answered Apr 03 '19 at 11:41

9

I solved this issue by downgrading to:

implementation 'androidx.room:room-runtime:2.1.0-alpha04'
annotationProcessor 'androidx.room:room-compiler:2.1.0-alpha04'

answered Apr 03 '19 at 11:41

Ahsan

131
2
3

Waheed Nazir · Answer 3 · 2019-04-03T11:39:56.570

Solved!

//Downgraded to alpha04.

implementation 'androidx.room:room-runtime:2.1.0-alpha04'
annotationProcessor 'androidx.room:room-compiler:2.1.0-alpha04'

// Other dependencies are..

implementation 'androidx.lifecycle:lifecycle-extensions:2.1.0-alpha03'
implementation 'androidx.lifecycle:lifecycle-viewmodel:2.1.0-alpha03'
implementation 'androidx.lifecycle:lifecycle-livedata:2.1.0-alpha03'
annotationProcessor 'androidx.lifecycle:lifecycle-compiler:2.1.0-alpha03'

// Removed this from project level gradle.
maven { url "https://kotlin.bintray.com/kotlinx/" }

Don't forget to Clean & Rebuild the project after these changes

score 2 · Answer 4 · answered Mar 27 '19 at 15:25

2

Like most errors that have something to do with Room, the error message that pops up the most is most unlikely to be your problem. For me it helped to raise the max Error count by adding :

gradle.projectsEvaluated {
    tasks.withType(JavaCompile) {
        options.compilerArgs << "-Xmaxerrs" << "1000"
    }
}

and then executing the gradle task:

 :app compileDebugJavaWithJavac

Then you will get a large list of errors, in your case the

Note: Failed to read get kotlin metadata for [Ljava.lang.Object;@79d6c4df

But somewhere in that list are your real errors like a wrong query or something like that. Fix those errors and rebuild the project, that works most of the time, but sometimes you have to invalidate the cache and restart Android Studio.

answered Mar 27 '19 at 15:25

glm9637

894
9
20

Do you mean to say actual errors are not currently displayed? What is the default value of Xmaxerrs? – dawn Mar 28 '19 at 04:46
1

For me at least that was the Problem, and somewhere in between was the Information that one query column did not match the object. I think the default value is 100 errors. – glm9637 Mar 28 '19 at 06:49
I did that but still couldn't see any errors that I understand. @glm9637 – dawn Apr 16 '19 at 10:28
1

try searching the console with this as regex: `^((?!(class|Databinding|Note: failed|\^)).)*$` it should mark those errors that have nothing to do with Kotlin or any uninteresting Databinding errors @dawn – glm9637 Apr 16 '19 at 13:41

score 2 · Answer 5 · answered Mar 29 '19 at 15:45

2

Invalidate caches and restart solved my problem. My room version is 2.1.0-alpha06 and I have also add the following dependency to my project repository:

 maven { url 'https://kotlin.bintray.com/kotlinx/' }

answered Mar 29 '19 at 15:45

Omar Faruq

69
5

Suhad Bin Zubair · Answer 6 · 2019-04-15T03:14:39.687

2

I got the same error, I updated the room libraries, but issue not fixed, then I did below steps, ... after that problem solved,

Step 1: Check @DataBase class in your project and check all tables (entities) are inserted

Step 2: Increment version number

Step 3: Add ".fallbackToDestructiveMigration()" before .build().

Don't forget to Clean & Rebuild the project after these changes

edited Apr 15 '19 at 03:14

answered Apr 15 '19 at 03:03

Suhad Bin Zubair

717
7
10

score 1 · Answer 7 · answered Apr 27 '19 at 06:17

As I was typing this answer, I was notified of 2.1.0-alpha07. It resolved all errors. Going back to 2.1.0-alpha06 broke the build again.

It turns out the new version resolved the errors for me.

Before trying to resolve the error, try updating Android Studio first. After updating Gradle, all dependencies, and AS from 3.3.2 to 3.4, I found errors I haven't encountered before, like

error: Room cannot pick a constructor since multiple constructors are suitable. Try to annotate unwanted constructors with @Ignore.
error: Cannot find setter for field.
There are multiple good constructors and Room will pick the no-arg constructor. You can use the @Ignore annotation to eliminate unwanted constructors.
error: Not sure how to convert a Cursor to this method's return type.

Once I fixed them, the build was successful and the app ran. I didn't need to add any additional maven repos mentioned in the accepted answer.

score 0 · Answer 8 · edited Mar 18 '19 at 19:26

0

Adding import androidx.room.Dao; and then re-importing it did the trick for me.

edited Mar 18 '19 at 19:26

ttulka

10,309
7
41
52

answered Mar 18 '19 at 19:18

Robko

1

score 0 · Answer 9 · answered May 21 '19 at 17:21

I solved by adding this to build.gradle (Module)

    androidTestImplementation "androidx.arch.core:coretesting:$rootProject.archLifecycleVersion"

In my build.gradle(Project)

ext {
    roomVersion = '2.1.0-alpha06'
    archLifecycleVersion = '2.0.0'
}

score 0 · Answer 10 · answered Jul 15 '19 at 12:17

Just change room_version in your gradle_module file in dependency block and change other room associated libraries you need. Use https://developer.android.com/jetpack/androidx/releases/room#2.2.0-alpha01 as an example. Try to use latest stable version of room.

score 0 · Answer 11 · answered Jan 15 '20 at 14:32

0

I have the same error and i used version 2.1.x-alpha and after updated to 2.2.3 the new version reported the error correctly and it was that one of my entities didn't have primary key

answered Jan 15 '20 at 14:32

Islam Assem

1,376
13
21

score -1 · Answer 12 · answered Mar 18 '19 at 16:47

I came across the same problem and fixed it by override the equals & hashCode methods of the object.
A possible solution for your case:

@Override
public int hashCode() { return (27 * fid + (name!= null ? name.hashCode() : 0)); }

And

@Override
public boolean equals(@Nullable Object obj) {
    if (this == obj) return true;
    if (!(obj instanceof Flock)) return false;
    Flock flock = (Flock) obj;
    if(fid != flock.fid) return false;
    return name != null ? name.equals(flock.name) : flock.name == null;
}

you will also need find a solution for the Date usage in Room, Room doesn't have a build in solution for a Date variable.

Adding a default constructor might also help. public Flock() {} — Thomas VC, Mar 18 '19 at 16:50

Note: Failed to read get kotlin metadata for [Ljava.lang.Object;@79d6c4df

12 Answers12