I’m attempting to read input events in Linux. I tried to use WatchService unusuccessfully and then migrated to Apache Commons IO, also unsuccessfully. I imagine that these character devices don’t generate filesystem events that either of these two mechanisms pick up?

import java.io.File;
import java.io.PrintStream;
import java.io.FileOutputStream;
import java.nio.charset.StandardCharsets;

import org.apache.commons.io.monitor.FileAlterationObserver;
import org.apache.commons.io.monitor.FileAlterationMonitor;
import org.apache.commons.io.monitor.FileAlterationListener;
import org.apache.commons.io.monitor.FileAlterationListenerAdaptor;

public class App
{
        public static void main(String[] args) throws Exception
        {
                File file = new File("/dev/tty0");
                FileOutputStream output = new FileOutputStream(file);
                PrintStream stream = new PrintStream(output, true, StandardCharsets.UTF_8);
                System.setOut(stream);
                System.setErr(stream);

                FileAlterationObserver observer = new FileAlterationObserver("/dev/input");
                FileAlterationMonitor monitor = new FileAlterationMonitor(1000l);
                FileAlterationListener listener = new FileAlterationListenerAdaptor()
                {
                        @Override
                        public void onFileCreate(File file)
                        {
                                System.out.println(file);
                                try{Thread.sleep(2000);}catch(Exception e){}
                                System.exit(0);
                        }

                        @Override
                        public void onFileDelete(File file)
                        {
                                System.out.println(file);
                                try{Thread.sleep(2000);}catch(Exception e){}
                                System.exit(0);
                        }

                        @Override
                        public void onFileChange(File file)
                        {
                                System.out.println(file);
                                try{Thread.sleep(2000);}catch(Exception e){}
                                System.exit(0);
                        }
                };
                observer.addListener(listener);
                monitor.addObserver(observer);
                monitor.start();
        }
}

This code generates no output onto /dev/tty0. My next step is to actually read from the character device /dev/input/js0 as suggested here. I’ve understood that the character device can be read in blocking or non-blocking mode. However, I’m unsure as to how to start. Does this involve opening/closing the stream periodically and some sort of polling interval? Does the stream remain open at all times and get placed and its subsequent operations get placed into a separate running thread?