Realm Helper Android

RealmHelper.java

public class RealmHelper {
    public static <T extends RealmObject> void save(T object) {
        Realm realm = Realm.getDefaultInstance();
        try {
            realm.beginTransaction();
            realm.copyToRealmOrUpdate(object);
            realm.commitTransaction();
        } finally {
            realm.close();
        }
    }

    public static <T extends RealmObject> void deleteAll(Class<T> clazz){
        Realm realm = Realm.getDefaultInstance();
        try {
            realm.beginTransaction();
            realm.delete(clazz);
            realm.commitTransaction();
        } finally {
            realm.close();
        }
    }

    public static <T extends RealmObject> void deleteWhere(Class<T> clazz, OnQuerySearch<T> where){
        Realm realm = Realm.getDefaultInstance();
        try {
            realm.beginTransaction();
            RealmQuery<T> query = realm.where(clazz);
            query = where.onQuery(query);
            RealmResults<T> listResults = query.findAll();
            if(listResults != null && listResults.size() > 0)
                listResults.deleteAllFromRealm();
            realm.commitTransaction();
        } finally {
            realm.close();
        }
    }

    public static <T extends RealmObject> T findFirst(Class<T> clazz){
        return findFirst(clazz, null);
    }

    public static <T extends RealmObject> T findFirst(Class<T> clazz, OnQuerySearch<T> querySearch){
        Realm realm = Realm.getDefaultInstance();
        try {
            RealmQuery<T> query = realm.where(clazz);
            if(querySearch != null)
                query = querySearch.onQuery(query);
            T data = query.findFirst();
            if(data != null) return realm.copyFromRealm(data);
            return null;
        }finally {
            realm.close();
        }
    }

    public static <T extends RealmObject> List<T> findAll(Class<T> clazz){
        return findAll(clazz, null);
    }

    public static <T extends RealmObject> List<T> findAll(Class<T> clazz, String sort){
        return findAll(clazz, sort, -1);
    }

    public static <T extends RealmObject> List<T> findAll(Class<T> clazz, String sort, int limit){
        return findAll(clazz, sort, limit, null);
    }
    public static <T extends RealmObject> List<T> findAll(Class<T> clazz, String sort, int limit, OnQuerySearch<T> querySearch){
        Realm realm = Realm.getDefaultInstance();
        try {
            RealmQuery<T> query = realm.where(clazz);
            if(querySearch != null)
                query = querySearch.onQuery(query);
            List<T> listData = TextUtils.isEmpty(sort) ? query.findAll() : query.findAllSorted(sort, Sort.DESCENDING);
            List<T> listResult = new ArrayList<>();
            if(listData != null && listData.size() > 0) {
                listResult = realm.copyFromRealm(listData);
            }
            if(limit > 0 && limit < listResult.size()) return listResult.subList(0, limit);
            return listResult;
        }finally {
            realm.close();
        }
    }

    public interface  OnQuerySearch<E extends RealmObject>{
        RealmQuery<E> onQuery(RealmQuery<E> query);
    }
}