title: Confusion about the size of references in the JVM spec
body: <p>The JVM spec states that references only take up one local variable slot( jvms12 2.6.1). Additionally it states that <code>double</code> and <code>long</code>, take up two local variable slots because they are 64-bit. </p>
  
  <p>Does this mean that all JVM compliant implementations must use 32-bit addressing? How do 64-bit JVMs handle this? Do they use 64 bit local variable slots, or do they use 2 slots for references?</p>