A reference to a MemberNameTable is going to be added to the InstanceKlass structure in the fix for:
  https://jbs.oracle.com/bugs/browse/JDK-8008511

It adds 4 bytes to each class but most of the time it is empty.

This is a email exchange on this topic:

On Apr 2, 2013, at 2:09 PM, Coleen Phillimore <coleen.phillimore@oracle.com> wrote:

>> Also, the decision how to represent the MNT depends on its future usage by the compiler team.
>> As we agreed, the compiler team is going to adjust the MNT to their needs
>> at some point when it is more convenient for them.
>> So that, could we make a final decision when the whole picture is ready?
>> It would be better to approach it in some steps.
>> Currently, this bug blocks other work on the JVMTI support of jsr-292.
>
> I don't know what the jsr 292 team has in store for this field but it's still a footprint cost that's for only a special case. So this is okay if you file a bug so that we can remove it and reimplement this table to be global or a hashtable.

FTR, I would prefer to reimplement it as an optional attribute of java.lang.Class, so that JDK code can access it. This will cut down on the number of native-to-Java transitions (JNI calls). By "optional attribute" I mean something like ReflectionData, or even a field of ReflectionData itself.

— John