Description Caspar D. 2010-08-02 05:30:51 EDT

When the remote end of a socket is closed, on the home end of the
connection that may either cause a -1 to be returned from
SocketChannel.read(ByteBuffer), or it may cause an IOException to be
thrown from that call, with the following trace:

java.io.IOException: An existing connection was forcibly closed by the remote host
  at sun.nio.ch.SocketDispatcher.read0(Native Method)
  at sun.nio.ch.SocketDispatcher.read(Unknown Source)
  at sun.nio.ch.IOUtil.readIntoNativeBuffer(Unknown Source)
  at sun.nio.ch.IOUtil.read(Unknown Source)
  at sun.nio.ch.SocketChannelImpl.read(Unknown Source)...

The former situation (-1) we handle gracefully, while in the latter
case we dump the stacktrace. See net4j.buffer.Buffer.java, line 154.

It seems there is no clear specification of when the method will
exhibit the one or the other behavior; it seems to rather depend on
how the process owning the socket was terminated, and whether or not
that process ran on a different host or not. See for example:

  http://www.coderanch.com/t/207367/sockets/java/Detecting-client-disconnection-events

As far as I can tell, the -1 and the exception signal the same
situation, i.e. remote socket closure. So we should handle both in the
same way.