PersistenceMigrationsSample/app/src/room2/java/com/example/android/persistence/migrations/UsersDatabase.java [32:69]:
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@TypeConverters(DateConverter.class)
public abstract class UsersDatabase extends RoomDatabase {

    private static UsersDatabase INSTANCE;

    public abstract UserDao userDao();

    private static final Object sLock = new Object();

    /**
     * Migrate from:
     * version 1 - using the SQLiteDatabase API
     * to
     * version 2 - using Room
     */
    @VisibleForTesting
    static final Migration MIGRATION_1_2 = new Migration(1, 2) {
        @Override
        public void migrate(SupportSQLiteDatabase database) {
            // Room uses an own database hash to uniquely identify the database
            // Since version 1 does not use Room, it doesn't have the database hash associated.
            // By implementing a Migration class, we're telling Room that it should use the data
            // from version 1 to version 2.
            // If no migration is provided, then the tables will be dropped and recreated.
            // Since we didn't alter the table, there's nothing else to do here.
        }
    };

    /**
     * Migrate from:
     * version 2 - using Room
     * to
     * version 3 - using Room where the {@link User} has an extra field: date
     */
    @VisibleForTesting
    static final Migration MIGRATION_2_3 = new Migration(2, 3) {
        @Override
        public void migrate(SupportSQLiteDatabase database) {
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PersistenceMigrationsSample/app/src/room3/java/com/example/android/persistence/migrations/UsersDatabase.java [32:69]:
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@TypeConverters(DateConverter.class)
public abstract class UsersDatabase extends RoomDatabase {

    private static UsersDatabase INSTANCE;

    public abstract UserDao userDao();

    private static final Object sLock = new Object();

    /**
     * Migrate from:
     * version 1 - using the SQLiteDatabase API
     * to
     * version 2 - using Room
     */
    @VisibleForTesting
    static final Migration MIGRATION_1_2 = new Migration(1, 2) {
        @Override
        public void migrate(SupportSQLiteDatabase database) {
            // Room uses an own database hash to uniquely identify the database
            // Since version 1 does not use Room, it doesn't have the database hash associated.
            // By implementing a Migration class, we're telling Room that it should use the data
            // from version 1 to version 2.
            // If no migration is provided, then the tables will be dropped and recreated.
            // Since we didn't alter the table, there's nothing else to do here.
        }
    };

    /**
     * Migrate from:
     * version 2 - using Room
     * to
     * version 3 - using Room where the {@link User} has an extra field: date
     */
    @VisibleForTesting
    static final Migration MIGRATION_2_3 = new Migration(2, 3) {
        @Override
        public void migrate(SupportSQLiteDatabase database) {
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