Code Review 7098719: -Dsun.net.maxDatagramSockets and Socket constructor does not work correctly with System.gc()

[Chris Hegarty]

Michael, Alan,

This is a follow up to CR 7073491 where the same issue was addressed in 
DatagramSocket. This CR proposes to address the same problem exposed 
through deprecated java.net.Socket(InetAddress host, int port, boolean 
stream).

The problem is in AbstractPlainSocketImpl.create(). If 
ResourceManager.beforeUdpCreate() throws an exception then fd is left 
set. When the finalizer for this object runs it will invoke close() and 
decrement the counter, thus double counting the close. It only happens 
via the finalizer because the impl is not returned to the application, 
because the original exception is thrown from a Socket constructor.

http://cr.openjdk.java.net/~chegar/7098719/webrev.00/webrev/

-Chris.