The following blocking operations are fiber friendly in the current prototype; these methods do not pin the carrier thread when the operation blocks.

APIMethodsNotes
java.net.Socketconnect, read, write, closeRelies on JEP 353
java.net.ServerSocketaccept, close



java.nio.channels.SocketChannelconnect, read, write, closeconnect, read, write, and close on the socket adaptor obtained via SocketChannel::socket also okay
java.nio.channels.ServerSocketChannelaccept, closeaccept and close on the socket adpator obtained via ServerSocketChannel::socket also okay
java.nio.channels.DatagramChannelread, receive, closewrite and send do not block
java.nio.channels.Pipe.SourceChannelread, close
java.nio.channels.Pipe.SinkChannelwrite, close


The following blocking operations are not currently fiber friendly; these methods pin the carrier thread when the operation blocks.

APIMethodsNotes
java.net.DatagramSocketreceiveNeed to investigate if receive can be done without synchronizing on the DatagramPacket (unspecified but long standing behavior)
java.nio.channels.SelectorselectSelection operations are specified to synchronize on the selector and the selected-key set. May not be a concern as code using fibers should not need to use non-blocking I/O and Selectors.
java.lang.ThreadinterruptIf a thread is interrupted when blocked in an I/O operation on an InterruptibleChannel then the channel is closed. The locking to support this is not yet fiber friendly so Thread.interrupt may pin the carrier thread while waiting for the blocking operations on the channel to abort.