RE: Cost of instantiating

I agree with those things, Paul, but at the same time that's something
"magic" under the covers.  Personally, I tend to avoid that sort of
thing unless there's a compelling reason for it.  My guess is that the
String literal is common enough (how many times have you used ""?) that
the compiler folks decided it was worth it.  But to do something like
that in general; me, I'd prefer doing it myself using a factory
function.

Also note that the intern() function in String requires that you create
the object anyway; you have to have the original String object in order
to look for it.  So I think maybe the construction overhead isn't saved,
only the additional memory.  And given the fact that, as you say, it
only makes sense for some specific Integers like 0 or 1, and suddenly
the memory savings aren't that great either.

Joe


> From: Paul Morgan
> 
> But the cost of a lookup is less than the cost of creating another
object.
> Might be worth it for something like Integer(0) or Integer(1) (good
chance
> to find that immutable) but maybe not for Integer(12345) (waste of
time to
> look for).
> 
> It's also a memory vs speed tradeoff.  You save JVM memory if you can
> reuse
> immutables.  Might be worth saving memory at the cost of slower object
> creation.   Could benefit other things like garbage collection.