Q:

Adding initial data in Realm Android

I'm using realm and all looks good until I try to add initial data in my database.
I followed the example in this answer, so in my class, that inherits from Application, I have the following:
public class MainApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        Realm.init(this);
        final Map<String, String> map = new LinkedHashMap();
        map.put("Key1", "value1");
        map.put("Key2", "value2");
        RealmConfiguration config = new RealmConfiguration.Builder().initialData(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                int i = 1;
                for (Map.Entry entry : map.entrySet()) {
                    realm.beginTransaction();
                    Category c = realm.createObject(Category.class, i++);
                    c.setName((String) entry.getKey());
                    c.setDescription("Category #" + entry.getValue());
                    realm.commitTransaction();
                }
                realm.close();
            }
        }).deleteRealmIfMigrationNeeded().name("realm.db").build();
        Realm.setDefaultConfiguration(config);
    }
}

And I thought this configuration should work, however I'm getting the following error:

java.lang.IllegalStateException: The Realm is already in a write transaction in /path/...

Is there something that I'm missing?
Thanks in advance.

A:

Remove realm.beginTransaction(), realm.commitTransaction() and realm.close() calls. The public void execute(Realm realm) is a method of Realm.Transaction class and it will handle starting and committing the transaction for you:
RealmConfiguration config = new RealmConfiguration.Builder().initialData(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                int i = 1;
                for (Map.Entry entry : map.entrySet()) {
                    Category c = realm.createObject(Category.class, i++);
                    c.setName((String) entry.getKey());
                    c.setDescription("Category #" + entry.getValue());
                }
            }
        }

