title: Instantiating core Volley objects
body: <p>What I'm a bit unsure about with Volley is the RequestQueue, ImageLoader objects and ImageLoader.ImageCache implementations.. </p>
  
  <p>In the examples I have come across they are instantiated in onCreate() but it doesn't seem to make sense to create a new request queue for each and every activity. I also have loads of activities and services and I will be using it everywhere. If I really do have to instantiate them in each Service or Activity, how expensive are they? </p>
  
  <p>What is best practice production apps are using to instantiate and access these objects?</p>