Nepherus' homework, except it won't help since I used java collections, because it's java

Iterate

public class Iterate {
    public static void main(String[] args) {
        new Iterate().run();
    }

    public void run() {
        long start=System.currentTimeMillis();
        InputStream in = this.getClass().getResourceAsStream("/numbers.txt");
        BufferedInputStream bis=new BufferedInputStream(in);
        Scanner scanner=new Scanner(bis);
        int counter=0;
        BitSet bits=new BitSet();
        while(scanner.hasNext()) {
            int i=scanner.nextInt();
            bits.set(i);
            counter++;
        }
        for (int i = bits.nextClearBit(999999); i >= 0; i = bits.nextSetBit(i+1)) {
            System.out.println(i);
        }
        long end=System.currentTimeMillis();
        System.out.printf("%d entries processed in %d ms%n",counter, end-start);
    }
}