Sync'ing up jdk7 at b50

[Alan Bateman]

Just a heads-up that I plan to push a change-set to jdk7 b50 to bring 
the nio2 implementation up to date (jdk7 has the socket-channel API 
updates since b36 but not the file system API, asynchronous I/O API, and 
other fixes that have accumulated in the interim). This will allow it be 
tested by the wide audience that consume the weekly promoted builds. 
Development (esp. API changes) will continue here and will be sync'ed in 
later builds.

-Alan.