A single threaded server using non-blocking I/O that can receive UTF-8-encoded string messages. Implemented using java.nio in Kotlin and serves as demo/example code.

Variable length UTF-8 encoded messages, up to a max receive buffer size each, with end message marker byte (0x00). Server does not explicitly acknowledge messages at application layer.

The NIOServer instance provides received messages through a concurrent bounded queue.

mvn install

Fire up server on localhost, port 9999:

./run-server.sh 9999

(This script runs the main function of class MainKt by executing jar.)

In some other terminal, send the server messages consisting of the file names in your home directory:

ls -1 $HOME|tr \\n \\0|nc -w1 localhost 9999

(Each message must be ended by a null byte.)

Now check server log.

It was just a fun exercise mainly to learn a bit about java.nio non-blocking I/O, the ByteBuffer and the Selector API.