如何数string里的字母数量

比如说一个string是“Chinese", 我要找出出现次数最多的字母，也就是e,请问这样的程序怎么写
----------------解决方案--------------------------------------------------------
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Count {
    public static void main(String args[]) {
        int maxCount = 0;
        char maxChar = 'a';
         
        String str = "Chinese";
        for (char ch='a'; ch<='z'; ch++) {
        int count=0;
        Pattern p = Pattern.compile(""+ch);
        Matcher m = p.matcher(str.toLowerCase());
        while(m.find())
        count++;
         
        if (count>maxCount) {
            maxCount=count;
            maxChar=ch;
        }
    }
    System.out.println(出现次数最多的字母是:"+maxChar+" "+maxCount);
     
    }
----------------解决方案--------------------------------------------------------