The scope of this issue has been extended to cover the default
implementation of the three new-style socket option method of
`SocketImpl` and `DatagramSocketImpl`. The associated CSR contains the
specific details. 

---

The `getOption` and `setOption` methods of the four java.net socket
types ( ServerSocket, Socket, DatagramSocket, and MulticastSocket ),
should conform to their specification. Specifically:

1) Throw NullPointerException if the option name is null.

   Specification:
     * @throws NullPointerException if name is {@code null}

   Example of existing behaviour:
     jshell> (new Socket()).setOption(null, 1);
     |  Exception java.lang.UnsupportedOperationException: unsupported option
     |        at PlainSocketImpl.setOption (PlainSocketImpl.java:72)
     |        at Socket.setOption (Socket.java:1760)
     |        at (#2:1)

2) Throw IllegalArgumentException when passed a bad value.

   A bad value is one of null ( since no specified options accept a
   null value ), or a value outside of the options textually specified
   range, e.g. StandardSocketOptions.SO_SNDBUF specifies "a negative
   size is not allowed". This applied to `setOption` only.

   Specification:
     * @throws IllegalArgumentException if the value is not valid for
     *         the option.

   The options that specify, either explicitly or implicitly, a value
   range (in StandardSocketOptions) are SO_RCVBUF, SO_SNDBUF, IP_TOS,
   and IP_MULTICAST_TTL.

   Example of existing behaviour:
     jshell> (new Socket()).setOption(StandardSocketOptions.SO_RCVBUF,-1);
     |  Exception java.net.SocketException: bad parameter for SO_SNDBUF or SO_RCVBUF
     |        at AbstractPlainSocketImpl.setOption (AbstractPlainSocketImpl.java:289)
     |        at SocketImpl.setOption (SocketImpl.java:384)
     |        at PlainSocketImpl.setOption (PlainSocketImpl.java:69)
     |        at Socket.setOption (Socket.java:1760)
     |        at (#1:1)

3) Throw an IOException after the socket has been closed. 

   Specification:
     * @throws IOException if an I/O error occurs, or if the socket is closed.

   Example of existing behaviour:
     jshell> var s = new Socket()
     s ==> Socket[unconnected]
     jshell> s.close()
     jshell> s.getOption(StandardSocketOptions.SO_RCVBUF)
     $8 ==> 131072