Android Firebase 2.4 IllegalStateException using new ref.updateChildren()

Question

When using Firebase 2.4 ref.updateChildren() with HashMap, other than HashMap (e.g. HashMap)

Answer 1

As in the code snippet from the Official Firebase Blog to avoid this issue one has to re-write custom structure like this:

Map newPost = new HashMap();
newPost.put("title", "New Post");
newPost.put("content", "Here is my new post!");

And then put it instead of custom data model:

Map updatedUserData = new HashMap();
updatedUserData.put("users/posts/" + newPostKey, true);
updatedUserData.put("posts/" + newPostKey, newPost);

Using custom data model instead of newPost causes IllegalStateException.