DouKaku?

import java.util.regex.*;
import java.io.*;

public class Decomment {

    static final Pattern COMMENT1 = Pattern.compile("/\\*.*?\\*/", Pattern.DOTALL);
    static final Pattern COMMENT2 = Pattern.compile("//.*");
    
    public static void main(String[] args) throws IOException {
        for (String name : args) {
            BufferedReader r = new BufferedReader(new FileReader(name));
            FileWriter w = new FileWriter(name + ".out");
            StringBuilder sb = new StringBuilder();
            String line;
            while ((line = r.readLine()) != null) {
                sb.append(line).append(System.getProperty("line.separator"));
            }
            String s1 = COMMENT1.matcher(sb).replaceAll("");
            String result = COMMENT2.matcher(s1).replaceAll("");
            w.write(result);
            w.close();
        }
    }
}