java stream map int stream to string

1String x2 = "hello";
2String newSortedString = "";
3Object[] y = x2.toLowerCase()
4                .chars()
5                .sorted()
6                .mapToObj(i -> (char) i)
7                .toArray();
8
9for (Object o: y) {
10  newSortedString = newSortedString.concat(o.toString());
11}
12
13System.out.println(newSortedString);