title: how the live objects are figured out in young generation collection?
body: <p>I understand that time taken by YGC is proportional to number of live objects in Eden. I also understand that how the live objects are figured out in Major collections (All the objects in thread stacks and static objects and further objects reachable from those objects transitively.)  </p>
  
  <p>But I dont understand how the live objects are figured out in young generation collection ?
  if it parses the thread stacks, then it need to parse eden + tenured space which is not the case I think. So how does JVM find the live objects in eden and copies them in <code>To Survivor</code> space ?    </p>