import java.util.*;

class Chara implements Comparable{
    String s;
    
    Chara(String s){
        this.s = s;
    }
    
    public boolean equals(Object o){
        Chara c = (Chara)o;
        
        return s.equals(c.s);
    }
    
    public int hashCode(){
        int result = 31;
        int c = s.length();
        result = 37* result + c;
        return result;
    }
    
    public int compareTo(Object o){
        Chara c = (Chara)o;
        int r =0;
        char ch1 = s.charAt(0);
        char ch2 = c.s.charAt(0);
        r = Character.toLowerCase(ch1) - Character.toLowerCase(ch2);
        
        if(r != 0){
            return r;
        }else{
            return ch2 - ch1 ;
        }
        
    }
    
    public String toString(){
        return s;
    }
}

public class aAbB {


    public static void main(String[] args) {
        
        List cc = new LinkedList();
                
        cc.add(new Chara("D"));
        cc.add(new Chara("d"));
        cc.add(new Chara("Bank"));
        cc.add(new Chara("chair"));
        cc.add(new Chara("apple"));
        cc.add(new Chara("Chat"));
        cc.add(new Chara("Andriod"));
        cc.add(new Chara("Egg"));
        cc.add(new Chara("bannana"));
        
        Collections.sort(cc);
        
        System.out.println(cc);
                
    }
}

------解决方案--------------------
java.lang.String

public int compareTo(String anotherString) {
	int len1 = count;
	int len2 = anotherString.count;
	int n = Math.min(len1, len2);
	char v1[] = value;
	char v2[] = anotherString.value;
	int i = offset;
	int j = anotherString.offset;

	if (i == j) {
	    int k = i;
	    int lim = n + i;
	    while (k < lim) {
		char c1 = v1[k];
		char c2 = v2[k];
		if (c1 != c2) {
		    return c1 - c2;
		}
		k++;
	    }
	} else {
	    while (n-- != 0) {
		char c1 = v1[i++];
		char c2 = v2[j++];
		if (c1 != c2) {
		    return c1 - c2;
		}
	    }
	}
	return len1 - len2;
   }

自己修改下。