Java sorts the number of occurrences of characters in a string

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
Import Java.util.List;
Import Java.util.Map;
/**
* continues to sort the number of occurrences of characters in the character set.
*
* @author Zhaoqing
*/
public class T {
public static void Main (String args[]) {
String str = 12 345678HFDJKSLAHFKJ932189OIEFSJKAR94WERFDSF ";
Map<character, keyvalue> Map = new Hashmap<character, keyvalue> ();
Char C;
KeyValue kv = null; 　　　
for (int i = 0; i < str.length (); i++) {
c = str.charat (i);
KV = Map.get (c); 　　　　
if (kv = = null) {
KV = new KeyValue ();
kv.ch = C;
Kv.count = 1;
Map.put (c, KV); 　　　
} else {
kv.count++;
　　
}
List<keyvalue> List = new arraylist<keyvalue> (Map.values ());
Collections.sort (list); 　　
for (KeyValue o:list) {
System.out.println (o.ch + "=" + O.count);

}
}
class KeyValue implements comparable {
public int compareTo (Object obj) {
if (obj instanceof keyvalue) {
KeyValue kv = (keyvalue) obj;
return kv.count-this.count; 　
}
Return-1;
}
Char ch;
int count;
}

Run results

f=5
j=3
k=3
s=3
9=3
d=2
e=2
a=2
h=2
3=2
2=2
1=2
r=2
4=2
8=2
o=1
l=1
i=1
w=1
7=1
6=1
5=1