Sort a single String in Java

toCharArray followed by Arrays.sort followed by a String constructor call:

import java.util.Arrays;

public class Test
{
    public static void main(String[] args)
    {
        String original = "edcba";
        char[] chars = original.toCharArray();
        Arrays.sort(chars);
        String sorted = new String(chars);
        System.out.println(sorted);
    }
}

EDIT: As tackline points out, this will fail if the string contains surrogate pairs or indeed composite characters (accent + e as separate chars) etc. At that point it gets a lot harder… hopefully you don’t need this 🙂 In addition, this is just ordering by ordinal, without taking capitalisation, accents or anything else into account.