This issue concerns closing a SocketChannel that has the SO_LINGER socket option enabled and the channel is registered with a Selector.
SO_LINGER is only specified for sockets configured in blocking mode but there are cases where libraries (or tests) may be enabling SO_LINGER on non-blocking sockets to a value of zero so that they can generate a RST to reset the connection. The behavior for the case that the channel is registered with a Selector has changed in JDK 11 (as part of JDK-8198562). In JDK 11, the peer will read EOF whereas in JDK 10 and older, the connection will be reset.
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