Sequence changes related with https://github.com/realm/realm-java/pull/3834

breaking.java

    @Test
    public void breaking_changes() throws InterruptedException {
        // # Global Realm listeners -- Both Realm & DynamicRealm#
        // ## The global Realm change listener will be called immediately when commitTransaction() on the same thread ##
        realm.addChangeListener(new RealmChangeListener<Realm>() {
            @Override
            public void onChange(Realm element) {
                // Notice this will be called 3rd in the next event loop in the old implementaion.
                RealmLog.info("This will be printed 2nd.");
            }
        });

        realm.executeTransaction(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                RealmLog.info("This will be printed 1st.");
            }
        });

        RealmLog.info("This will be printed 3rd."); // Notice in the old version, this will be called 2nd.

        // ## The global Realm change listener may be called immediately when beginTransaction() on the same thread ##
        final CountDownLatch bgCommitDone = new CountDownLatch(1);
        realm.executeTransactionAsync(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                bgCommitDone.countDown();
            }
        });

        bgCommitDone.await();
        realm.addChangeListener(new RealmChangeListener<Realm>() {
            @Override
            public void onChange(Realm element) {
                // Notice this will be called only once in the next event loop in the old implementation.
                RealmLog.info("This will be printed 2 times.");
            }
        });

        // beginTransaction will advance read the Realm to the latest version, and if it is different from current
        // version, the change listener will be called.
        realm.beginTransaction();
        // Notice in the old version, this will be called 2nd.
        RealmLog.info("This will be printed after first time listener called.");
        realm.commitTransaction();

        RealmLog.info("This will be printed at last."); // Notice in the old version, this will be called 2nd.

        // ## The global listener won't be called if it is added later after commitTransaction on the same thread. ##
        realm.beginTransaction();
        realm.commitTransaction();

        realm.addChangeListener(new RealmChangeListener<Realm>() {
            @Override
            public void onChange(Realm element) {
                // Notice this will be called in the next event loop in the old implenmentation.
                RealmLog.info("This won't be called.");
            }
        });

        // # Listeners on RealmObject and DynamicRealmObject #
        // ## All the changes for the global change listeners could be applied to the RealmObject listeners. ##
        // ## Calling load on findFirstAsync()'s, and if it cannot find any results, the async query won't be rerun.  ##
        AllTypes allTypes = realm.where(AllTypes.class).findFirst();
        assertTrue(allTypes.isValid() == false); // It cannot find any object match the query.
        // In the old  implementation, if calling load() and it cannot find any object, the query will rerun and return
        // the results until it can find an object match the query. But it is a wrong behavior. Think about
        // following code.
        AllTypes allTypes1 = realm.where(AllTypes.class).findFirst();
        assertTrue(allTypes1.isValid() == true); // It finds an object match the query.
        realm.beginTransaction();
        // In the old implementation, if the object gets deleted here and there is a pending COMPLETE_ASYNC_OBJECT event
        // in the queue, the allTypes1 will become a different object which is a wrong behavior.
        allTypes1.deleteFromRealm();
        realm.commitTransaction();

        // # RealmResults.distinct() will create a new RealmResults
        RealmResults<AllTypes> results1 = realm.where(AllTypes.class).findAll();
        RealmResults<AllTypes> results2 = results1.distinct(AllTypes.FIELD_DOUBLE);
        // For the old implementation, the results2 will be the same with results1. But we have a bug tracking it, so
        // this would be more like a bug fix than breaking change.
        assertTrue(results1 != results2);
    }