Arraylist Add To New Recyclerview

Hi I am trying to add a new item to my chat, I use RXJava2, to make call to my REST API to get the chat data, with this nested json response. But I get an NullPointer when I try to

Solution 1:

I think you need to initialized private ArrayList messageArrayList; you need to create new ArrayList before adding contain on this list

Solution 2:

When you instantiate ChatMessages object the user field in that object is null. you must call setUser(ChatMessageUser user) method and pass an existing user object to it before calling add.getUser().setUserId(userid).