can any one explain about the below code which is Dining Philosophers Problem..

//Dining Philosophers Problem
import java.util.Random;
class Monitor {
int phil_States[] = new int[5];   // 0=not_waiting, 1=waiting // 2=eating
boolean fork_States[] = new boolean[5];  // false = in use, true = free
Monitor() {        // constructor
   for(int i=0;i<5;i++) {
synchronized void print_State()
System.out.println();        // newline
for(int i=0;i<5;i++)
     System.out.print(" " + phil_States[i]);        
synchronized void ask_to_eat(int pId)
   while(!fork_States[pId] || !fork_States[(pId+1)%4])
   {    // while it can't have both forks, wait
      phil_States[pId] = 1;  
  catch(InterruptedException e){} // it gets released
   }    // by a process doing a call to notify()
   phil_States[pId] = 2;  // eating
   fork_States[pId] = false;  // in use
   fork_States[(pId+1)%4] = false;
synchronized void ask_to_leave(int pId)
     fork_States[pId] = true; // available
     fork_States[(pId+1)%4] = true;
     phil_States[pId] = 0;  // thinking
     notify(); // free the Phil that has waited the longest
class Diners {
public static void main(String args[]) { // execution of the whole
   Monitor m = new Monitor(); // thing begins here
   Timer t = new Timer(m);  // make a new timer
   Phil p[] = new Phil[5];  // make an array of 5 refs to Phils
   for(int i=0; i<5; i++)
      p[i] = new Phil(i,m,t); // create the phils and start them
class Phil implements Runnable {
Monitor m;
Timer t;
Random r = new Random();  // Random number generator object
int pId;
float time;
Phil(int pId, Monitor m, Timer t) { // constructor
   System.out.println(pId + "is started: ");
   this.pId = pId;
   this.m = m;
   this.t = t;
   new Thread(this, "Phil").start(); // make a new thread and start it
public void run() {   // must override run, this is what
   for(int i=0; i<20; i++) {  // is executed when the thread starts
     m.ask_to_eat(pId);  // running
     time = 1000*r.nextFloat();
     try {Thread.sleep((int)time);} catch(Exception e){}
     time = 1000*r.nextFloat();
     try {Thread.sleep((int)time);} catch(Exception e){}
t.report_Stop();   // tell the timer this one is done
class Timer implements Runnable {
Monitor m;
int completed;
Timer(Monitor m) {   // constructor
   this.m = m;
   new Thread(this, "Tim").start(); // make a new thread and start it
public void report_Stop() {
public void run() {   // must override run(), this is 
   while(completed!=5) {  // what happens when the thread
      m.print_State();  // begins
      try {Thread.sleep(500);} catch(Exception e){}

Explain what about it? You haven't asked a question.

explain what it does..

Member Avatar for iamthwee

Looks like a threaded program. What d you know about threads so far?

explain what it does..

Well, I would say it is a possible solution to the Dining Philosophers problem, which one quick Google search provided the explanation:

Are you wanting someone to walk you through how the code works step by step? I'm still not understanding what your question is exactly.

seeing as the solution to the problem is contained in the official Sun tutorial, I wonder what the problem is :)

Can someone tell please, this solution prevents a problem of starvation?

commented: zombie homework kiddo -3
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