title: do I need to restore all variables onResume?
body: <p>I had bad experience with <code>static class variables</code> since their values are lost when the class unloads.  Therefore I avoid them alltogether.</p>
  
  <p>Now I am (probably overly) worried even with "normal" variables.</p>
  
  <blockquote>
    <p>I'm not sure if their value also might get lost in certain
    circumstances like disruptions by a call, low memory or anything else.</p>
  </blockquote>
  
  <p><strong>Can I rely on the variables hold their values 100% ?</strong> or</p>
  
  <p><strong>do I ensure some kind of valid restore for all activity variables?</strong></p>
  
  <p>Thanks!</p>