title: Fragments with empty constructors vs. newInstance
body: <p>If I am creating a Fragment class, I've seen written everywhere that it is a good idea to include an empty constructor (although I'm not sure why, because I always assumed Java had an empty constructor invoked under the hood for any Java class as long as you don't create a constructor with arguments, and Android doesn't like you making Fragments with constructors with arguments anyway). </p>
  
  <p>But if I am making a newInstance() method (so I can set up my Bundle with default arguments), do I have to create the empty constructor?</p>
  
  <p>If it is enough to include newInstance() and not an empty constructor, could I do this for all my fragments even if there are no arguments in the bundle? Is there any downside to this?</p>