how to sort a string alphabetically java [closed]

Answer 1

You can do this using Arrays.sort, if you put the characters into an array first. (It must be an array of Character objects rather than char primitives, in order to use a custom case-insensitive comparator.)

// put the characters into an array
Character[] chars = new Character[str.length()];
for (int i = 0; i < chars.length; i++)
    chars[i] = str.charAt(i);

// sort the array
Arrays.sort(chars, new Comparator() {
    public int compare(Character c1, Character c2) {
        int cmp = Character.compare(
            Character.toLowerCase(c1.charValue()),
            Character.toLowerCase(c2.charValue())
        );
        if (cmp != 0) return cmp;
        return Character.compare(c1.charValue(), c2.charValue());
    }
});

// rebuild the string
StringBuilder sb = new StringBuilder(chars.length);
for (char c : chars) sb.append(c);
str = sb.toString();