life is short, you need stream
import java.util.*; import java.util.stream.*; public class Main { public static void main(String[] args) { Scanner in = new Scanner(System.in); Stream.of(in.nextLine().split("")).sorted().map(System.out::printf); } }
import java.util.*; import java.util.stream.*; public class Main { public static void main(String[] args) { Scanner in = new Scanner(System.in); int[] count = new int['z' - '0' + 1]; for (char c : in.nextLine().toCharArray()) { count[c - '0']++; } for (int i = 0; i < count.length; i++) { while (count[i]-- > 0){ System.out.print((char)(i + '0')); } } } }