Method Pointers

[Peter Levart]

On Sunday, March 25, 2012 06:37:00 PM Brian Goetz wrote:
> > OK, so this is simply an implementation hack, which happens to improve
> > performance, and has the side effect of probably confusing new users,
> > rather than a deliberate, unreliable design feature?
> 
> Which is almost identical to something we do in javac -- fold together
> identical string literals within a class into the same constant pool
> entry, resulting in strings appearing to be == accidentally.  

I allways thought this was a feature not an accidential consequence. It's 
written down in the String's javadoc as:

"All literal strings and string-valued constant expressions are interned. 
String literals are defined in §3.10.5 of the Java Language Specification"

So perhaps we are talking about two different things here:

1) identical strings in the same class are folded into the same constant pool 
entry (as optimization of class file size)
2) string literals are interned (as a language/library feature)

The fact that identical literal strings apear to be == is therefore a language 
feature, not an optimization side-consequence.

Peter

> We don't
> do it to confuse the users, but it may have that effect anyway.