firebasemigration.java

    private void fixFbDb(){

        DatabaseReference entireDb = FirebaseDatabase.getInstance().getReference();
        final DatabaseReference goodRef = FirebaseDatabase.getInstance().getReference("vanilla-messages-debug");
        entireDb.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                for(DataSnapshot snapshot: dataSnapshot.getChildren()){
                    if(snapshot.getKey().startsWith("vanilla-messages-debug-")){
                        String badMessageId = snapshot.getKey().split("vanilla-messages-debug-")[1];
                        LogUtils.d("FBDB - to migrate", badMessageId);
                        //if(badMessageId.equalsIgnoreCase("125-13043")){
                            //List<Map<String, Object>> list = new ArrayList<>();
                            for(DataSnapshot s: snapshot.getChildren()){
                                LogUtils.d("FBDB - snap", s.getValue().toString());
                                //Map<String, Object> map = new HashMap<>();
                                //map.put(s.getKey(), s.getValue());
                                //list.add(map);
                                //LogUtils.d("FBDB", "Map is " + map.toString());
                                goodRef.child(badMessageId).child(s.getKey()).setValue(s.getValue());
                            }
                        //}
                    }
                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });
        goodRef.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                for(DataSnapshot snapshot: dataSnapshot.getChildren()){
                    //LogUtils.d("FBDB - good", snapshot.getKey());
                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

//        DatabaseReference sRef = FirebaseDatabase.getInstance().getReference("vanilla-messages-125-13043");
//        sRef.addChildEventListener(new ChildEventListener() {
//            @Override
//            public void onChildAdded(DataSnapshot dataSnapshot, String s) {
//                LogUtils.d("FBDB", "got " + dataSnapshot.toString());
//                //FirebaseDatabase.getInstance().getReference("vanilla-messages/randomchildref").setValue(dataSnapshot);
//                Map<String, Object> map = new HashMap<>();
//                map.put(dataSnapshot.getKey(), dataSnapshot.getValue());
//                LogUtils.d("FBDB", "Map is " + map.toString());
//                goodRef.child("randomchild2");
//            }
//
//            @Override
//            public void onChildChanged(DataSnapshot dataSnapshot, String s) {
//
//            }
//
//            @Override
//            public void onChildRemoved(DataSnapshot dataSnapshot) {
//
//            }
//
//            @Override
//            public void onChildMoved(DataSnapshot dataSnapshot, String s) {
//
//            }
//
//            @Override
//            public void onCancelled(DatabaseError databaseError) {
//
//            }
//        });
    }

firebasemigration2.java

    private void migrateDb(){
        final DatabaseReference sourceRef = FirebaseDatabase.getInstance().getReference("vanilla-messages-debug");
        final DatabaseReference destinationRef = FirebaseDatabase.getInstance().getReference("vanilla-debug/messages");

        sourceRef.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                LogUtils.d("FBDB dataSnapshot", dataSnapshot.getKey());
                for(DataSnapshot snapshot: dataSnapshot.getChildren()){
                    LogUtils.d("FBDB children of ", snapshot.getKey());
                    for(DataSnapshot snapChild: snapshot.getChildren()){
                        LogUtils.d("FBDB", snapChild.getKey());
                        destinationRef.child(snapshot.getKey()).push().setValue(snapChild.getValue());
                    }
                    //add complementary link to find new app
                    long now = System.currentTimeMillis();
                    ForumMessage updateMessage = new ForumMessage("Your messages will soon be unavailable! \n " +
                            "Please update your app to continue messaging https://goo.gl/P9qRT0", "Asoriba", "0", now);
                    sourceRef.child(snapshot.getKey()).child(String.valueOf(now)).setValue(updateMessage.toString());

                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });
    }