title: Explain the trivia: How many live collections are in a typical heap?
body: <p>I am reading through the presentation <a href="http://domino.research.ibm.com/comm/research_people.nsf/pages/sevitsky.pubs.html/%24FILE/oopsla08%20memory-efficient%20java%20slides.pdf" rel="nofollow">"Building memory efficient Java applications"</a>, and saw that on slide 11 they ask the question: "How many live collections in a typical heap?"</p>
  
  <p>The answer is 10k to millions.</p>
  
  <p>I will be very humble and say that I do not know where I would begin with this question. </p>
  
  <p>What is a live collection vs a "not live collection"?  By collections, do they mean java.util.collections? </p>
  
  <p>Do collections live in the heap?  I suppose since they are not allocated on the stack, that only leaves the heap.  </p>
  
  <p>What is implied by the revelation that there are 10k to millions of collections living on the heap?  I can only assume that this is a bad thing.</p>