Dining Philosopher.....FUN!

import java.io.*;
import java.util.*;

class philosopher extends Thread {

  private static int TIMES_2_EAT      = 50;
  private static int times_eaten      = 0;
  private static int num_philosophers = 0;
  private static int sleep_multiplier = 5; 
  private static boolean DEBUG        = false;
 
  // supports a maximum of 10 philosophers
  private static int [] chopsticks = {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1};
  private int phil_number;
  
  Random generator = new Random();

  public philosopher( int n ) {
    phil_number = n;
    num_philosophers++;
  }

  private void eat() {
    int time_2_eat = 1 + generator.nextInt(10);
    try {
      sleep(time_2_eat*sleep_multiplier);
    } catch ( InterruptedException e) {};  
  }

  private void think() {
    int time_2_think = 2 + generator.nextInt(20);
    try {
      sleep(time_2_think*sleep_multiplier);
    } catch ( InterruptedException e) {};  
  }
   
  private void get_Chopsticks ( int p_num ) {
    synchronized(chopsticks) {
      while (chopsticks[p_num] >= 0) {
        try {
          if (DEBUG) System.out.println("  Phil number " + p_num + " waiting for chopstick");
          chopsticks.wait();
        } catch (InterruptedException e) {};	
      } 
      chopsticks[p_num] = p_num;
      if (DEBUG) System.out.println("Philosopher " + p_num + " picked up " +
          	         p_num + " chopstick.");

      while (chopsticks[(p_num+1) % num_philosophers] >= 0) {
        try {
          if (DEBUG) System.out.println("  Phil number " + p_num + " waiting for chopstick");
          chopsticks.wait();
        } catch (InterruptedException e) {};	
      } 
      chopsticks[(p_num+1) % num_philosophers] = p_num;
      if (DEBUG) System.out.println("Philosopher " + p_num + " picked up " +
  	                  (p_num+1)%num_philosophers + " chopstick.");
      times_eaten++;
    } // end sync section
  }
  
  private void replace_chopsticks (int p_num) {
    synchronized(chopsticks){
      chopsticks[p_num] = -1;
      chopsticks[(p_num+1) % num_philosophers] = -1;
      if (DEBUG) System.out.println("Philosopher " + p_num + " put down chopsticks.");
      chopsticks.notifyAll();
    } // end synch section
  }  

  public void run() {
    int times_I_have_eaten = 0;
    
    System.out.println("Philosopher " + phil_number + " ready to eat.");

    while ( times_eaten < TIMES_2_EAT ) {
      think();

      // now get ready to eat
      get_Chopsticks(phil_number);

      eat();
      System.out.println("Philosopher " + phil_number + " just ate " + 
                         times_I_have_eaten + "th meal.");
      
      // put down chopsticks
      replace_chopsticks(phil_number);
      times_I_have_eaten++;
    }

    // nothing left to eat, so leave the table
    num_philosophers--;
    
    System.out.println("Philosopher " + phil_number + " has eaten: " +
	               times_I_have_eaten + " times.");
    System.out.println("  Number phils left: " + num_philosophers);
    System.out.println("  Total meals eaten: " + times_eaten);

    synchronized (chopsticks) {
      chopsticks.notifyAll();		// one last notify before you leave
    }
  }

}  // end class philosopher
public class DiningPhils_fixsync {
  public static void main( String[] args ) throws IOException {
    
    String input_string; 
    BufferedReader in_from_keyboard = new BufferedReader (
	         new InputStreamReader (System.in) );
    System.out.println("Enter the number of philosophers: ");
    input_string = in_from_keyboard.readLine();
    int num_philosophers = Integer.parseInt(input_string);
    num_philosophers = (num_philosophers < 0 || num_philosophers > 10)
                     ? 4 : num_philosophers;
    System.out.println("Running with " + num_philosophers + " philosophers");

    int i;
        
    for (i=0; i<num_philosophers; i++) {
      philosopher p = new philosopher( i );
      new Thread( p ).start();
    }

  }//end main
}//end public class ThreadTester