public static void main(String[] args) {

char[] a = {'a', 'b', 'c', 'd', 'e', 'a', 'b', 'a', 'b', 'a', 'c', 'd', 'e', 'j', 'k', 'r', 't', 'y', 'i', 'u', 's', 'e', 'x', 's', 'u', 'x'};

System.out.println(a);

sort(a);

System.out.println(a);

}

public static void sort(char[] a) {

int R = 26;

int[] count = new int[R + 1];

int N = a.length;

char[] aux = new char[N];

for (int i = 0; i < N; i++)

count[a[i] - 'a' + 1]++;

for (int r = 0; r < R; r++)

count[r + 1] += count[r];

for (int i = 0; i < N; i++)

aux[count[a[i] - 'a']++] = a[i];

for (int i = 0; i < N; i++)

a[i] = aux[i];

}