On 9/03/2015 3:56 PM, John Rose wrote:
On Mar 8, 2015, at 4:32 PM, David Holmes <david.hol...@oracle.com
<mailto:david.hol...@oracle.com>> wrote:
Yes it could but why should it be? You have a singleton instance with
all instance methods, so cached state should be in an instance field
not a static one.
No, the singleton instance is *not* currently used, so it would add new
constraints on the optimizer to begin using fields from it.
No sure what you mean by it isn't used - code invokes instance methods
on the unsafe instance all over the JDK ???
Only the non-nullness of its reference is significant. It has no state
by design.
Given all existing methods are stateless I can't tell if this a
statement of intent (ie it must never have state) or simply a statement
of fact as all the methods are stateless. If it should in fact never
have any state then that should be documented.
Put another way: It is a uniquely simple empty singleton object.
To pass the unsafe access check, the JIT need only check that some
non-null reference is available.
And JVM JITs are very good at exactly that check.
So the reason to use a static field from an instance method is simply an
artifact of the interaction of our JIT with this class?
David
— John
