The old and new connection checking tests used by org.jboss.remoting.transport.socket.ClientSocketWrapper and ServerSocketWrapper interact in a negative way. In the old test, turned on when socket.check_connection is set to true, ClientSocketWrapper sends a 1, ServerSocketWrapper returns it, and if ClientSocketWrapper is able to read a byte, the test passes. But in the new test, ServerSocketWrapper writes two 254 bytes as it is closing. If ClientSocketWrapper is doing the old test and it reads one of these bytes, it thinks the test has passed. It should check for the actual value of the returned byte.