Java Scanner Input in Separate Thread

I have a multi-threaded command line app. It is a web service client with a pool of 10 threads that churns away, sending requests, batch-style, to a server.

But it runs for a few days, and sometimes further down the pipeline, the queues start getting backed up. So I want to go to the client, press - or + and have that increase or decrease a Thread.sleep(waitingTime), to take pressure off the server.

I tried running a Scanner in a separate thread, but it didn't seem to work. Has anyone managed to get non-blocking I/O working in Java? I presume it's possible, but I'm giving up for now.

Edit: Added test code as per request

package test;

import java.io.*;
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * Created by djb on 2015/06/03.
 */
public class ThreadTest {
    public ThreadTest() {
    }

    static long rand = 10000;

    public static void main(String args[])
    {

        ExecutorService executor = Executors.newFixedThreadPool(5);

        File f = new File("C:\\code\\ThreadTest\\text.csv");
        try {

            Runnable keyPressThread = new ThreadTest.KeyPressThread();
            Thread t = new Thread(keyPressThread);
            t.start();

            BufferedReader br = new BufferedReader(new FileReader(f));

            String line;

            while ((line = br.readLine()) != null)
            {

                try {
                    final String copy = line;

                    executor.execute(new Runnable() {
                        @Override
                        public void run() {
                            try {

                                System.out.println(rand);
                                Thread.sleep(rand);
                                System.out.println(copy);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                        }
                    });


                } catch (Exception e)
                {
                    e.printStackTrace();
                }

            }

        } catch (Exception e)
        {
            e.printStackTrace();
        }




    }


    public static class KeyPressThread implements Runnable {

        Scanner inputReader = new Scanner(System.in);

        //Method that gets called when the object is instantiated
        public KeyPressThread() {
        }

        public void run() {
            String input = inputReader.next();
            if (input.equals("["))
            {
                rand+=100;
                System.out.println("Pressed [");
            }
            if (input.equals("]"))
            {
                rand-=100;
                System.out.println("Pressed ]");
            }
        }

    }



}