Problema dos Comedodes-Dadeiros

rw.java

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Semaphore;

public class Main {
    private Semaphore empty, full, readers, writers;
    private List<Double> buffer;
    private List<Thread> threads;

    public class Reader implements Runnable {
        private int id;

        public Reader(int id) {
            this.id = id;

            System.out.println("Leitor " + id + " criado.");
        }

        @Override
        public void run() {
            for (int i = 0; i < 10; ++i) {
                try {
                    Thread.sleep((int) (Math.random() * 100));
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                try {
                    full.acquire();
                    readers.acquire();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                System.out.println("Leitor " + id + " começa a escrever no buffer...");
                //buffer.add(Math.random());
                try {
                    Thread.sleep((int) (Math.random() * 100));
                } catch (InterruptedException e) {
                }
                System.out.println("Leitor " + id + " termina de escrever no buffer...");

                readers.release();
                empty.release();
            }
        }
    }

    public class Writer implements Runnable {
        private int id;

        public Writer(int id) {
            this.id = id;

            System.out.println("Escritor " + id + " criado.");
        }

        @Override
        public void run() {
            for (int i = 0; i < 10; ++i) {
                try {
                    Thread.sleep((int) (Math.random() * 100));
                } catch (InterruptedException e) {
                }

                try {
                    empty.acquire();
                    writers.acquire();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                System.out.println("Escritor " + id + " começa a ler do buffer...");
                try {
                    Thread.sleep((int) (Math.random() * 100));
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println("Escritor " + id + " termina de ler do buffer...");

                writers.release();
                full.release();
            }
        }
    }

    public Main() {
        int num_leitores = (int) (Math.random() * 30) + 5,
                num_escritores = (int) (Math.random() * 30) + 5,
                tam_buffer = 10;

        empty = new Semaphore(tam_buffer);
        full = new Semaphore(0);
        readers = new Semaphore(1);
        writers = new Semaphore(1);
        threads = new ArrayList<>(num_escritores + num_leitores);

        for (int i = 0; i < num_leitores; ++i) {
            Reader r = new Reader(i);
            threads.add(new Thread(r));
        }
        for (int i = 0; i < num_escritores; ++i) {
            Writer w = new Writer(i);
            threads.add(new Thread(w));
        }
        for (Thread t : threads) {
            t.start();
        }
        for (Thread t : threads) {
            try {
                t.join();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        Main m = new Main();
    }
}