void implCloseChannel(SelectableChannel sc) throws IOException

Closes a selectable channel.

This method is invoked by the channel's close method in order to perform the actual work of closing the channel. This method is only invoked if the channel has not yet been closed, and it is never invoked more than once by the channel's close implementation.

An implementation of this method must arrange for any other thread that is blocked in an I/O operation upon the channel to return immediately, either by throwing an exception or by returning normally. If the channel is registered with one or more Selectors then the file descriptor should not be released until the implReleaseChannel method is invoked.

void implReleaseChannel(SelectableChannel sc) throws IOException

Release the file descriptor and any resources for a selectable channel that closed while registered with one or more Selectors.

This method is for cases where a channel is closed when registered with one or more Selectors. A channel may remain registered for some time after it is closed. This method is invoked when the channel is eventually deregistered from the last Selector that it was registered with. It is invoked at most once.