Java Argument Parser

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

public class ArgParser{

    public static void main(String[] args) {
        Map<String, List<String>> parsedArgs = ParseArgs(args);
        Map<String, Integer> rules = new HashMap<String, Integer>();
        rules.put("filmes", 3);
        rules.put("episodios", 2);
        rules.put("generos", 1);
        ValidateArgs(parsedArgs, rules);

        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 HashMap<String, List<String>>();
        List<String> subArgs = null;

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

        return result;
    }

    public static void ValidateArgs(Map<String, List<String>> args, Map<String, Integer> rules) {
        for(Map.Entry<String, Integer> rule: rules.entrySet()) {
            List<String> subArgs = args.get(rule.getKey());
            if(subArgs == null || subArgs.size() != rule.getValue())
                throw new InputMismatchException("Expected subargument count " + rule.getValue());
        }
    }
}