Summary: Dynamically allocate memory for getmntent
Reviewed-by: yan

8028792: (ch) Channels native code needs to be checked for methods calling JNI with pending excepitons
Summary: added null checks to JNI functoin call return values
Reviewed-by: chegar, coffeys

Reviewed-by: chegar, ksrini

Reviewed-by: andrew

Reviewed-by: darcy, weijun

4313887: New I/O: Improved filesystem interface
4607272: New I/O: Support asynchronous I/O
Reviewed-by: sherman, chegar