- What is the difference between connection and read timeout for sockets?
The connection timeout is the timeout in making the initial connection; i.e. completing the TCP connection handshake. The read timeout is the timeout on waiting to read data1. If the server (or network) fails to deliver any data <timeout> seconds after the client makes a socket read call, a read timeout error will be raised.
- What does connection timeout set to "infinity" mean? In what situation can it remain in an infinitive loop? and what can trigger that the infinity-loop dies?
It means that the connection attempt can potentially block for ever. There is no infinite loop, but the attempt to connect can be unblocked by another thread closing the socket. (A Thread.interrupt() call may also do the trick ... not sure.)
- What does read timeout set to "infinity" mean? In what situation can it remain in an infinite loop? What can trigger that the infinite loop to end?
It means that a call to read on the socket stream may block for ever. Once again there is no infinite loop, but the read can be unblocked by a Thread.interrupt() call, closing the socket, and (of course) the other end sending data or closing the connection.
1 - It is not ... as one commenter thought ... the timeout on how long a socket can be open, or idle.