Interview Question for Senior QA Engineer(Mobile) at Rearden Commerce:

private String removeDups(String in) {
        if (in == null) return null;
        char[] inAr = in.toCharArray();
        Set<Integer> outSet = new HashSet<Integer>();
        List<Integer> outList = new ArrayList<Integer>();
        for (char ch : inAr) {
            if (outSet.add((int) ch))
                outList.add((int)ch);
        }
        char[] outAr = new char[outList.size()];
        Iterator<Integer> it = outList.iterator();
        for (int i = 0; it.hasNext(); i++) {
            int outInt = it.next();
            outAr[i] = (char)outInt;
        }
        return String.copyValueOf(outAr);
    }