Java Argument Parser V3

import java.util.Map;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.ArrayList;
import java.util.InputMismatchException;

public class ArgParser{

    public static void main(String[] args) {
        Map<String, List<String>> parsedArgs = ParseArgs(args);
        Map<String, String[]> rules = new HashMap<String, String[]>();

        rules.put("filmes", new String[]{"nome_ator1", "nome_ator2", "decada"});
        rules.put("episodios", new String[]{"nome_ator", "titulo_serie"});
        rules.put("generos", new String[]{"nome_ator"});

        if(!ValidateArgs(parsedArgs, rules, true))
            return;

        for(Map.Entry<String, List<String>> arg: parsedArgs.entrySet()) {
            System.out.println(arg.getKey());

            for(String subArg: arg.getValue())
                System.out.println("\t" + subArg);
        }
    }

    public static Map<String, List<String>> ParseArgs(String[] args) {
        Map<String, List<String>> result = new LinkedHashMap<String, List<String>>();
        List<String> subArgs = null;

        for(String arg: args)
            if(arg.startsWith("-"))
                result.put(arg.substring(1), subArgs = new ArrayList<String>());
            else if(subArgs != null)
                subArgs.add(arg);
            else
                result.put(arg, null);

        return result;
    }

    public static Boolean ValidateArgs(Map<String, List<String>> args, Map<String, String[]> rules, Boolean aLeastOne) {
        Boolean result = true;

        if(aLeastOne && args.isEmpty())
            System.err.println("E necessario ao menos um parametro!");

        for(Map.Entry<String, List<String>> arg: args.entrySet()) {
            if(rules.containsKey(arg.getKey())) {
                String[] subArgs = rules.get(arg.getKey());

                if(subArgs != null && (arg.getValue() == null || arg.getValue().size() != subArgs.length)) {
                    String Msg = String.format("O parametro <-%s> espera %d subargumentos.\nModo de uso: <-%s>"
                                              , arg.getKey(), subArgs.length, arg.getKey());

                    for(String str: subArgs)
                        Msg += " <" + str + ">";

                    System.err.println(Msg);
                    result = false;
                }
            } else {
                System.err.println(String.format("Parametro desconhecido <%s%s>"
                                                , arg.getValue() != null ? "-" : "", arg.getKey()));
                result = false;
            }
        }

        return result;
    }
}