RFR: 8176472: Lazily create ModuleEntryTable

[Lois Foltan]

Hi Rachel,

Looks good.  One minor comment:

src/share/vm/classfile/classLoaderData.cpp
- line #565, since you construct the unnamed module via a method in 
ModuleEntryTable, please consider adding another method to delete it.  
That way you can put in that method a comment explaining why it does not 
need to have "unlink_entry" called on it as well since it is not in the 
hashtable.

Thanks,
Lois

On 4/14/2017 10:34 AM, Rachel Protacio wrote:
> Hello!
>
> Please review this enhancement which moves the unnamed module out of 
> the ModuleEntryTable and into the ClassLoaderData so that the MET can 
> be lazily created only when other modules are present. The 
> PackageTable size has also been updated to be more realistic. These 
> two changes save the VM from losing memory space unnecessarily in the 
> module data structures.
>
> Tested with JPRT and RBT tiers 2-5.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8176472
> Open webrev: http://cr.openjdk.java.net/~rprotacio/8176472.00/
>
> Thank you,
> Rachel