I posted a related question a few days ago, along with code, and did not get
any responses.  So here goes a different version.  I can post code, but
there's a lot, so I can also post only specific sections.

I'm working on a port forwarder and the first step is to get the local port
to listen to all incoming data.  I've created a ServerSocket and a
ServerSocketChannel, then I've created a Selector and registered the
ServerSocketChannel with a Selector for OP_ACCEPT.  Then I go into a loop
where I wait on the Selector.select() function.  I've tried this with it
waiting forever and with it waiting 50 milliseconds, then, if nothing,
waiting again (which also leaves time to check the stopForwarding flag).

I have a Perl program I'm using to send data to the ServerSocket.  For now
I'm just sending text, but in the long run, of course, it could be any kind
of binary data.  The Perl program sends one message, then sleeps for a
second, then goes into a loop where it sends a message, sleeps a second,
then sends another message for 10 times.

In the Java program, Selector.select() picks up the first data coming in to
the ServerSocket, the SelectionKey is registered, it is acceptable, and I
create a Socket and SocketChannel, then register the SocketChannel (for
OP_READ) with the same Selector the ServerSocketChannel is registered with.
It does see the first message sent to the socket and receives it properly.
I make sure I cancel the keys, both after the Socket is created AND after
the read operation.  Then the program *should* go to the top of the loop,
wait again and receive the next line of data from the Perl program through
the socket.

This is where it stops working and it seems dead.  Println statements show
the socket is still alive, not closed, not even half-closed, but that 2nd
stream of data is NEVER detected.  The Selector never responds to any new
readable operation.

As I said, I've posted something similar with code and didn't get any
replies.  I've used, as close as possible, the code in different tutorials
and examples I've seen online, but there's nothing focusing on this.  After
the first data stream, then a pause, neither the Socket or Selector
responds again.  I've tried re-running the Perl program to see if it would
open a new socket again, and it doesn't.

What could make a socket or selector seem to die or freeze after its first
burst of data?  My best guess is this is a Selector problem, but I'm doing
everything the way I've seen in examples.  I have some questions, but I
don't if any are helpful, or just me grabbing at straws:

Is there a problem registering more than one SocketChannel with the same
Selector?

Other than key.cancel() is there something else that must be done to make
sure the Selector is ready for the "next round?"

Why doesn't the ServerSocket want to create more sockets each time a new
message from my Perl program comes in?

Any suggestions or help are welcome.

Thanks!

Hal