title: Memory requirements of an Object reference on a 64 bit JVM
body: <p>A reference to an Object on a 32 bit JVM (at least on Hotspot) takes up 4 bytes.</p>
  
  <p>Does the 64 bit Hotspot JVM need 8 bytes? Or is some clever compression going on?
  If not, every <code>Object[]</code> would require twice as much heap memory, which I somehow think (hope, expect) is not the case.</p>
  
  <p><strong>Update/extra question</strong>: Does this really matter, or is this a negligible increase, because most references point to objects that are much larger than a few bytes (whereas one might argue that those objects are in turn mostly comprised of references to other objects)?</p>