want to make a program that selects out prime numbers. don't get why my program doesn't work
<p>whenever I try to run this program, it first shows "The prime's upper bound?" After inserting an integer and pressing enter, I don't see anything then. I want it to display some "false" values, but I can't find where the problem is. And the Java doesn't show where the problem is.</p>

<pre><code>import java.util.Scanner;

public class Lab11 {

    static int n;
    boolean [] primedetermine = new boolean [n];
    int [] list;

    public static void main (String[]args) {
        Scanner in = new Scanner (System.in);
        System.out.print ("The prime's upper bound? ");
        int max = in.nextInt();
        boolean prime [] = new boolean [max];
        computePrimes (prime);
    }

    public static void computePrimes(boolean[] primedetermine) {
        for (int x = 0; x&lt;n; x++) {
            primedetermine [x] = false;
        }
        for (int prm = 2; prm &lt;= n; prm++) {
            for (int prm2 = 2; prm * prm2 &lt;= 21; prm++) {
                primedetermine [prm * prm2 -1] = true;
            }
        }
        for (int x = 1; x&lt;=n; x++){
            if (primedetermine[x-1] == false);
                System.out.println(primedetermine[x-1]);
            }
        }
    }   
}   
</code></pre>