Java.Lang.NullPointerException -- Array Problem -- Couldn't fixed

Java.Lang.NullPointerException -- Array Problem -- Couldn't fixed

[Mr.Spark]

Hi Guys, I could not solve this problem, when I tried to throw an
exception the code will not be executed to see

the results.

I think the problem is with the array .

The Code :


import java.util.Random;

public class RunAlgorithm {

	static int n = 3; // Number of processes

	public static void main(String[] args) {

		int random_id;
		int Lowest_id;

		Random rn = new Random();
		SecurityModule[] s = new SecurityModule[n];

		// Initializing Security Modules

		for (int i = 0; i < n; i++) {
			s[i].ID = 0;
			s[i].State = false;
		}

		// Generating Random ID numbers for the Security Modules

		for (int i = 0; i < n; i++) {
			random_id = rn.nextInt(99) + 1;
			s[i].ID = random_id;                                    -- the
problem is in this line
			log("Random ID = " + random_id);

		}

		// To get the lowest ID

		Lowest_id = GetLowestID(s);
		System.out.println(" The Lowest ID is: " + Lowest_id);

		// The initiator with the lowest ID will generate a random number K
> 1

		int k = rn.nextInt(9) + 2;
		log("Round = " + k);

		// Generating a random number i in {1,2,3,...n}

		int i = rn.nextInt(3) + 1;
		log("i = " + i);
	}

	public static int GetLowestID(SecurityModule s[]) {

		int LowestID = s[0].ID;
		for (int i = 1, limit = s.length; i < limit; ++i) {
			if (s[i].ID < LowestID)
				LowestID = s[i].ID;
		}
		return LowestID;
	}



}

I hope that I can find a solution for this problem.

Thanks guys ..

Re: Java.Lang.NullPointerException -- Array Problem -- Couldn't fixed

[Jeffrey R. Carter]

Here's the problem:

> import java.util.Random;

You're using Java instead of Ada.

-- 
Jeff Carter
"Don't knock masturbation. It's sex with someone I love."
Annie Hall
45

Re: Java.Lang.NullPointerException -- Array Problem -- Couldn't fixed

[(see below)]

On 25/02/2010 01:04, in article
735e9720-4b06-46bb-8602-e04590473f57@z19g2000yqk.googlegroups.com,
"Mr.Spark" <malmanea@gmail.com> wrote:

> I hope that I can find a solution for this problem.
> 
> Thanks guys ..

I am resisting. I AM resisting ...

-- 
Bill Findlay
<surname><forename> chez blueyonder.co.uk

Re: Java.Lang.NullPointerException -- Array Problem -- Couldn't fixed

[John B. Matthews]

In article 
<735e9720-4b06-46bb-8602-e04590473f57@z19g2000yqk.googlegroups.com>,
 "Mr.Spark" <malmanea@gmail.com> wrote:

> Hi Guys, I could not solve this problem, when I tried to throw an 
> exception the code will not be executed to see the results.
> I think the problem is with the array.

Yes, the array had been created, but the elements were null.

I have guessed the missing pieces of your program, fixed the formatting 
and altered your getLowestId method. Note that java.util.Random is 
unsuitable for security. Followups to comp.lang.java.security.

[...]

import java.util.Random;

public class RunAlgorithm {

    static int n = 3; // Number of processes

    public static void main(String[] args) {
        int randomId;
        int lowestId;
        Random rn = new Random();
        SecurityModule[] s = new SecurityModule[n];

        // Initializing Security Modules
        for (int i = 0; i < n; i++) {
            s[i] = new SecurityModule();
        }

        // Generating Random ID numbers for the Security Modules
        for (SecurityModule sm : s) {
            randomId = rn.nextInt(99) + 1;
            sm.id = randomId; // the problem is in this line
            log("Random ID = " + randomId);
        }

        // To get the lowest ID
        lowestId = getLowestId(s);
        log("Lowest ID is: " + lowestId);

        // The initiator with the lowest ID will
        // generate a random number K > 1
        int k = rn.nextInt(9) + 2;
        log("Round = " + k);

        // Generating a random number i in {1,2,3,...n}
        int i = rn.nextInt(3) + 1;
        log("i = " + i);
    }

    private static int getLowestId(SecurityModule s[]) {

        int lowestId = Integer.MAX_VALUE;
        for (SecurityModule sm : s) {
            if (sm.id < lowestId) {
                lowestId = sm.id;
            }
        }
        return lowestId;
    }

    private static void log(String s) {
        System.out.println(s);
    }

    private static class SecurityModule {
        int id;
        boolean state;
    }
}

-- 
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>