title: Declaring classes in AndroidManifest.xml
body: <p>I understand that, in Android, all activities must be declared within the manifest. Is this true to all .java files in the project? </p>
  
  <p>I have a few classes that aren't activities (not directly related to an UI) and i'm unsure whether I need to declare them in the manifest.</p>
  
  <p>Thanks!</p>