RFR 6642881: Improve performance of Class.getClassLoader()

[Joel Borggrén-Franck]

Hi,

On 19 jun 2014, at 20:46, Coleen Phillimore <coleen.phillimore at oracle.com> wrote:
> On 6/17/14, 12:38 AM, Joel Borggrén-Franck wrote:
>>> 
>> Have you considered hiding the Class.classLoader field from reflection? I’m not sure it is necessary but I’m not to keen on the idea of people poking at this field with Unsafe (which should go away in 9 but …).
> 
> I don't know how to hide the field from reflection.  It's a private final field so you need to get priviledges to make it setAccessible.  If you mean injecting it on the JVM side, the reason for this change is so that the JIT compilers can inline this call and not have to call into the JVM to get the class loader.
> 

There is sun.reflect.Reflection.registerFieldsToFilter() that hides a field from being found using reflection. It might very well be the case that private and final is enough, I haven’t thought this through 100%. On the other hand, is there a reason to give users access through the field instead of having to use Class.getClassLoader()?

cheers
/Joel