Random Key Generator in Java

import java.util.*;
/**
 * This will generate a random key of n length
 *
 * @author  Shaun_B
 * @version 2013-02-06
 * @note    This is a bit over-kill, the code could be condensed down
 *      quite a bit, but I'll leave you to figure out which bits
 *      could be made redundant, because I'm good like that.
 */
public class KeyGenerator
{
    public static byte getChar( byte x )
    {
        // Our look-up table:
        byte [] character =
        {
            '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',
            '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '!', '@', '#',
            '$', '%', '^', '&', '*', '(', ')'
        };
        // Error checking, in case a number is out of range (shouldn't happen, but always
        // best to be safe:
        if (x<0 || x>45)
        {
            // Generates a random number between 0 and 45:
            Random randomNum = new Random();
            int rnd = randomNum.nextInt(46);
            // Returns random value:
            return (byte)character[(byte)rnd];
        }
        else
        {
            // Otherwise, we're okay:
            return (byte)character[x];
        }
    }
    public static void main (String [] a)
    {
        // Key length:
        int lengthOfKey = 12;
        // Temp variable for key:
        String generatedKey = "";
        // Generates a new instance of a random number or something:
        Random randomNum = new Random();
        // Generates the random key in this loop:
        for(int i=0; i<lengthOfKey; i++)
        {
            // Gets random number between 0 and 45:
            int random = randomNum.nextInt(46);
            // Calls the getChar method above, concatenating it to the String above:
            generatedKey=generatedKey + (char)(getChar((byte)random));
        }
        // Now we print it:
        System.out.printf("The generated key is: %s\n",generatedKey);
    }
}