DouKaku?

import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StreamTokenizer;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

public class CharCounter {
    public static void main(String[] args) throws Exception {
        Hashtable<Character, Count> counts = new Hashtable<Character, Count>();
        ZipFile file = new ZipFile(args[0]);
        Enumeration<? extends ZipEntry> entries = file.entries();
        while (entries.hasMoreElements()) {
            ZipEntry entry = entries.nextElement();
            if (!entry.getName().endsWith(".java")) continue;
            Reader src = new InputStreamReader(file.getInputStream(entry));
            StreamTokenizer tokenizer = new StreamTokenizer(src);
            tokenizer.resetSyntax();
            tokenizer.slashSlashComments(true);
            tokenizer.slashStarComments(true);
            while (tokenizer.nextToken() != StreamTokenizer.TT_EOF) {
                if (tokenizer.ttype == StreamTokenizer.TT_EOL) continue;
                char c = (char)tokenizer.ttype;
                Count count = counts.get(c);
                if (count == null) {
                    count = new Count(c);
                    counts.put(c, count);
                }
                count.n++;
            }
        }
        Vector<Count> ranking = new Vector<Count>();
        ranking.addAll(counts.values());
        Collections.sort(ranking);
        for (int i = 0; i < ranking.size(); i++) {
            System.out.println(ranking.get(i));
        }
    }
    static class Count implements Comparable<Count> {
        char c;
        int n = 0;
        Count(char c) {
            this.c = c;
        }
        public int compareTo(Count o) {
            return (o.n == this.n)? 0 : (o.n < this.n)? -1 : 1;
        }
        public String toString() {
            if (c < ' ') {
                return String.format("\\u%04x", (int)c) + "\t" + n;
            }
            return "'" + c + "'\t" + n;
        }
    }
}