java stream map int stream to string
String x2 = "hello";
String newSortedString = "";
Object[] y = x2.toLowerCase()
.chars()
.sorted()
.mapToObj(i -> (char) i)
.toArray();
for (Object o: y) {
newSortedString = newSortedString.concat(o.toString());
}
System.out.println(newSortedString);