DouKaku?

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

public class Decomment2 {
    static final String LITERAL = "(?:\"(?:\\\\.|[^\"])*\")|(?:\'(?:\\\\.|[^\'])*\')";
    static final String COMMENT1 = "(?s:/\\*.*?\\*/)";
    static final String COMMENT2 = "//.*";
    static final String SPACES = "\\s+";
    static final Pattern DECOM_PAT = Pattern.compile("(" + LITERAL + ")|((" + 
            COMMENT1 + "|" + COMMENT2 + "|" + SPACES + ")+)");
    static final String LINE_SEPARATOR = System.getProperty("line.separator");
    
    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(LINE_SEPARATOR);
            }
            Matcher m = DECOM_PAT.matcher(sb);
            StringBuffer replace = new StringBuffer();
            while (m.find()) {
                if (m.group(2) != null && m.group(2).length() > 0) {
                    m.appendReplacement(replace, " ");
                } else {
                    m.appendReplacement(replace, "$1");
                }
            }
            m.appendTail(replace);
            w.write(replace.toString());
            w.close();
        }
    }
}