Random Password Generation Tool?

I am looking to create a simple application that creates random passwords for user accounts. For example you either runt the class or (if using swing) click a generate button and it creates a random password for you using the selected amount of characters. Is there an easy way to do this or does anybody have any suggestions?

What you could do is create a string containing all the valid characters for a password, and use a loop to go for however many characters you want the password to be, and chose a random character from that string. If you need more clarification then just reply.

Consider leaving out the characters that people always get confused and are hard to distinquish in typical displays, such as the letters i and l and numeral 1 - also the letter O and numeral 0 from the pool of characters. Your users will thank you.
Bill

Here is some code that does something similar. It creates a random 15 character username (which is essentially a password). You should be able to modify it to mkae it do what you want.

package com.filenabber.nator.utils;
import java.io.*;
import java.util.*;

/**
 * Generates random mailinator usernames. Only uses 0-9, and a-z even 
 * though there are other usernames that are valid.
 * 
 * @author Brian Pipa
 * @version 1.0
 */
public class RandomUsername {
    /**
     * Random number generator
     */
    static Random generator = new Random();
    /**
     * Thh characters to use for usernames
     */
    static char[] validChars = new char[] {
            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd',
            'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r',
            's', 't', 'u', 'v', 'w', 'x', 'y', 'z'
        };
    static {
        Random generator = new Random();
    }
    /**
     * Generates a single random username
     * 
     * @return the random username
     */
    public static String generateUsername() {
        StringBuffer sbuf = new StringBuffer();
        int randomInt;
        for (int i = 0; i < 15; i++) {
            randomInt = generator.nextInt(35);
            sbuf.append(validChars[randomInt]);
        }
        return sbuf.toString();
    }
    /**
     * For testing only.
     *  Outputs 3 random usernames
     * 
     * @param args none
     */
    public static void main(String[] args) {
        RandomUsername ru = new RandomUsername();
        System.out.println(ru.generateUsername());
        System.out.println(ru.generateUsername());
        System.out.println(ru.generateUsername());
    }
}

Brian

re leaving some out ... I leave out the vowels - avoids accidentally generating offensive words (enough monkeys, enough typewriters ...) and skips those I 1 O 0 problems.
Another idea ... if you can find a free dictionary with a few thousand words, you could randomly select two or three words. Much easier to remember than a random string of letters & numbers. I still remember my first Compuserve password from 20 years ago was "water boldly".

To shorten your string of chars work you can use the ascii method to include all numbers, lower case letters and upper case letters.
_________________________________________________________
char [] Chars = new char [63];
int counter = 0;
for (int i = 48 ; i < 123 ; i++)
{
counter++;
//ignore all other chars
if (i == 58)
i = 65;
if (i == 91)
i = 97;
/*
//remove the comments if you want remove all vowels
//add and remove vowels as necessary
char ch = (char) i;
if (ch == 'a' || ch == 'e' || ch == 'o' || ch == 'u' || ch == 'i' || ch == 'y' || ch == 'A' || ch == 'E' || ch == 'O' || ch == 'U' || ch == 'I' || ch == 'Y')
counter--;
else */
Chars [counter] = (char) i;

}
________________________________________________________
Just something you might want to use for future as well.

B.G