[{“Name”:“Java SE 1.4”,“GroupName”:null},{“Name”:“Java SE 5”,“GroupName”:null},{“Name”:“Java SE 6”,“GroupName”:null},{“Name”:“Java SE 7”,“GroupName”:null},{“Name”:“Java SE 8”,“GroupName”:null},{“Name”:“Java SE 9 (Early Access)”,“GroupName”:null}]
[SelectionKey](<https://docs.oracle.com/javase/7/docs/api/java/nio/channels/SelectionKey.html>) defines the different selectable operations and information between its Selector and Channel. In particular, the attachment can be used to store connection-related information.
Handling OP_READ is pretty straight-forward. However, care should be taken when dealing with OP_WRITE: most of the time, data can be written to sockets so the event will keep firing. Make sure to register OP_WRITE only before you want to write data (see that answer).
Also, OP_CONNECT should be cancelled once the Channel has connected (because, well, it is connected. See this and that answers on SO). Hence the OP_CONNECT removal after finishConnect() succeeded.