title: What happens after I run rebuild project in Android Studio?
body: <p>The document <a href="http://www.jetbrains.com/idea/help/rebuilding-project.html?search=reb" rel="nofollow noreferrer">http://www.jetbrains.com/idea/help/rebuilding-project.html?search=reb</a> only tells me how to rebuild a project.</p>
  
  <p>I don't know what does it mean to rebuild a project (<code>Menu --&gt; Build --&gt; Rebuild Project</code>), will it clean all edit cache?  I find the size of the project reduced after I run rebuild project?</p>
  
  <p>What does it mean to clear a project in Android Studio?</p>