Java - Android如何将List从一个类返回到多个类？

I'm trying to create a reusable Class on Android that fetches Users data from a Firebase Database, creates a list of Users Models, and returns that list to any other classes that might need the list. But I'm not being able to do it. I won't bother you with all the code, but what I got is basically this:I'm trying to create a reusable Class on Androi