3.6 Server Implemented with NIO

NIO vs BIO

	BIO	NIO
	ServerSocket	ServerSocketChannel
	Socket	SocketChannel
		Selector
		SelectionKey

Common Questions

An Exception and Infinite Loop Occur When the Client Closes

The reason is that the return value of channel.read(buffer) was not checked. A return value of -1 means that the client has closed the connection and reading cannot continue.

Why Is NIO Called Non-Blocking If selector.select Blocks?

selector.select//blocking
selector.select(1000)//non-blocking
selector.wakeup//wake up selector

What Does SelectionKey.OP_WRITE Mean?

It means that the underlying buffer has space available for writing.