csharp, 149 bytes

Result

AC

Code [DL]

using System;public class Test{public static void Main(){var l=Console.ReadLine().ToCharArray();Array.Sort(l);Console.WriteLine(string.Join("",l));}}

stdin

1159849299100322510441198263053099043995553733561105391565418654782494489952889018637440434099132118

stdout

0000000000111111111111112222222333333333334444444444444555555555555666667778888888889999999999999999

stderr

strace