JAVA字符排序问题

class C implements Comparator
{
    public int compare(Object arg0, Object arg1)
    {
        String s1 = arg0.toString().toLowerCase();
        String s2 = arg1.toString().toLowerCase();
        return s1.compareTo(s2);
    }
}

class Ideone
{
    public static void main (String[] args) throws java.lang.Exception
    {
        String[] a = new String[] { "a", "b", "c", "A", "B", "C" };  
        Arrays.sort(a, new C());  
        for (int i = 0; i < a.length; i++)  
            System.out.println(a[i]);  
    }
}