Custom realm for static roles

MyRealm.java

import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authc.AuthenticationInfo;
import org.apache.shiro.authc.AuthenticationToken;
import org.apache.shiro.authc.SimpleAuthenticationInfo;
import org.apache.shiro.authc.UsernamePasswordToken;
import org.apache.shiro.authz.AuthorizationException;
import org.apache.shiro.authz.AuthorizationInfo;
import org.apache.shiro.authz.Permission;
import org.apache.shiro.authz.SimpleAuthorizationInfo;
import org.apache.shiro.realm.AuthorizingRealm;
import org.apache.shiro.subject.PrincipalCollection;

import com.google.inject.Inject;
import com.img.server.dao.UsuarioDao;
import com.img.server.domain.JoinedUsuarioRol;
import com.img.server.domain.Rol;
import com.img.server.domain.Usuario;
import com.img.server.util.PasswordEncryptionService;

//http://shiro-user.582556.n2.nabble.com/How-to-add-a-role-to-the-subject-td5562700.html
public class MyRealm extends AuthorizingRealm{

  @Inject UsuarioDao udao;
	@Inject PasswordEncryptionService pes;
	
	/**
	this function loads user authorization data from "userManager" data source (database)
	User, Role are custom POJOs (beans) and are loaded from database.  
	WildcardPermission implements shiros Permission interface, so my permissions in database gets accepted by shiro security
	**/
	@Override
	protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principals) {
		Set<String>			roles			= new HashSet<String>();
		Collection<String>	principalsList	= principals.byType(String.class);
		
		if (principalsList.isEmpty()) {
			throw new AuthorizationException("Empty principals list!");
		}

		//LOADING STUFF FOR PRINCIPAL
		for (String username : principalsList) {
			Usuario user = udao.getUser(username);
			List<JoinedUsuarioRol> userRoles = udao.getRoles(user);
			for(JoinedUsuarioRol userRol : userRoles){
				Rol rol = userRol.getRol();
				roles.add(rol.getDescripcion());
			}
			 
		}
		
		SimpleAuthorizationInfo info = new SimpleAuthorizationInfo(roles);	
		info.setRoles(roles); //fill in roles 
		return info;
	}

	@Override
	protected AuthenticationInfo doGetAuthenticationInfo(
			AuthenticationToken token) throws AuthenticationException {
		UsernamePasswordToken upToken = (UsernamePasswordToken) token;
		if (upToken.getUsername() == null || upToken.getUsername().isEmpty()) {
			throw new AuthenticationException("Authentication failed");
		}
		String username = upToken.getUsername();
		String password = String.valueOf(upToken.getPassword());
		
		Usuario user = udao.getUser(username);
		if(user == null)
			throw new AuthenticationException("Authentication failed");
		
		byte[] encryptedPassword = user.getClave();
		byte[] salt = user.getSalt();
		
		try {
			if(!pes.authenticate(password, encryptedPassword, salt)){
				throw new AuthenticationException("Authentication failed");
			}
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		} catch (InvalidKeySpecException e) {
			e.printStackTrace();
		}
		
		
		return new SimpleAuthenticationInfo(username, password, getName());
	}

}