Java – Room database not implemented

I

was trying the new Room ORM from googles Android Architecture Components and I followed the documentation, but when I ran my code, I got the java.lang.RuntimeException: cannot find implementation for com.zeyad.usecases.app。 User database. UserDatabase_Impl does not exist

Here is my code :

Gradle Project:

allprojects {
repositories {
    jcenter()
    maven { url 'https://jitpack.io' }
    maven { url 'https://maven.google.com' }
}
}

Gradient module:

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

User:

@Entity(tableName = "User")
public class User {

static final String LOGIN = "login";
    private static final String ID = "id", AVATAR_URL = "avatar_url";
    @PrimaryKey
    @SerializedName(LOGIN)
    @ColumnInfo(name = LOGIN)
    String login;

@SerializedName(ID)
    @ColumnInfo(name = ID)
    int id;

@SerializedName(AVATAR_URL)
    @ColumnInfo(name = AVATAR_URL)
    String avatarUrl;

public User() {
    }

public User(String login, int id, String avatarUrl) {
        this.login = login;
        this.id = id;
        this.avatarUrl = avatarUrl;
    }

public static boolean isEmpty(User user) {
        return user == null || (user.login == null && user.avatarUrl == null);
    }

public String getLogin() {
        return login;
    }

public void setLogin(String login) {
        this.login = login;
    }

public int getId() {
        return id;
    }

public void setId(int id) {
        this.id = id;
    }

public String getAvatarUrl() {
        return avatarUrl;
    }

public void setAvatarUrl(String avatarUrl) {
        this.avatarUrl = avatarUrl;
    }

@Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

User user = (User) o;

return id == user.id && (login != null ? login.equals(user.login) : user.login == null
                && (avatarUrl != null ? avatarUrl.equals(user.avatarUrl) : user.avatarUrl == null));
    }

@Override
    public int hashCode() {
        int result = login != null ? login.hashCode() : 0;
        result = 31 * result + id;
        result = 31 * result + (avatarUrl != null ? avatarUrl.hashCode() : 0);
        return result;
    }
}

User database:

@Database(entities = {User.class}, version = 1)
public abstract class UserDatabase extends RoomDatabase {
    public abstract RoomBaseDao roomBaseDao();
}

RoomBaseDao:

@Dao
public interface RoomBaseDao {

@Insert(onConflict = OnConflictStrategy.REPLACE)
    void insertItemsReplace(User... objects);

@Update(onConflict = OnConflictStrategy.REPLACE)
    void updateItemsReplace(User... objects);

@Delete
    void deleteItem(User object);
}

App at creation time:

UserDatabase gDb = Room.databaseBuilder(this, UserDatabase.class, "test-db").build();  throws the exception above

Thanks in advance.

In my case, I’m using an older version of ButterKnife, which requires the android-apt plugin. So I updated ButterKnife (now using the comment processor) and removed the plugin declaration in the Gradle file.

Maybe it’s not exactly your problem, but maybe it will help others.