Erro com login Struts2!

public setPassword(String password) {
 
}

public void validate() {
    if ( StringUtils.isBlank(username) ) {  
        addActionError("Type a login!");  
    }  
    if ( StringUtils.isBlank(password) ) {  
        addActionError("Type a password!");  
    } 
}

package net.Agile2Go.view.actions.user;

import net.Agile2Go.domain.entities.User;
import net.Agile2Go.domain.repositories.UserRepository;
import net.Agile2Go.infrastructure.util.security.DisableSecurityAction;
import net.Agile2Go.view.actions.BasicAction;

import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;
import org.apache.struts2.convention.annotation.Action;
import org.apache.struts2.convention.annotation.Namespace;
import org.apache.struts2.convention.annotation.ParentPackage;
import org.apache.struts2.convention.annotation.Result;
import org.apache.struts2.convention.annotation.ResultPath;

import com.opensymphony.xwork2.ModelDriven;

@Namespace(value = "/")
@ResultPath(value = "/")
@ParentPackage(value = "default")
public class UserAction extends BasicAction implements ModelDriven<User>,
													   DisableSecurityAction {
	/**
	 * Atributo de serialização, informa a versão da classe para o conteiner
	 */
	private static final long serialVersionUID = 8278524612322334361L;

	/**
	 * Atributo de log, grava mensagens e avisos durante a execução do sistema
	 */
	private Logger log = Logger.getLogger(getClass());

	/**
	 * Caminhos das páginas jsps
	 */
	private static final String PAGINA_LOGIN = "/login.jsp";
	// private static final String PAGINA_ADM_HOME =
	// "/WEB-INF/content/admin/home.jsp";
	private static final String PAGINA_USER_HOME = "/jsp/home.jsp";

	/**
	 * Atributo que permite efetuar as operações referente a entidade usuário
	 */
	private UserRepository repository;

	/**
	 * Atributo que representa um usuário
	 */
	private User user;

	/**
	 * Login do usuário
	 */
	private String username;

	/**
	 * Senha do usuário
	 */
	private String password;
	
	/**
	 * Este bloco de código será executado no construtor logo após a chamada de
	 * super(), para que o user não start com null.
	 */
	{
		user = user == null ? new User() : user;
	}

	@Action(value = "login", results = {
			@Result(name = SUCCESS, location = PAGINA_USER_HOME),
			@Result(name = INPUT, location = PAGINA_LOGIN),
			@Result(name = ERROR, location = PAGINA_LOGIN)})
	public String login () {
		try {
			if ( StringUtils.isBlank(username) ) {
				addActionError("Type a login!");
			}
			if ( StringUtils.isBlank(password) ) {
				addActionError("Type a password!");
			}
			if ( getActionErrors().size() > 0 ) {
				return INPUT;
			}
			user.setLogin(username);
			user.setPassword(password);
			user = repository.userWithLogin(user.getLogin(), user.getPassword());
			if ( user == null ) {
				addActionError("User not found in the database!");
				return INPUT;
			}
			session.put("user", user);
			return SUCCESS;
		} catch (Exception e) {
			log.error(e.getLocalizedMessage(), e);
			addActionError("A expected error has ocurred!");
			session.clear();
			return ERROR;
		}
	}
	
	public final String getUsername() {
		return username;
	}

	public final void setUsername(String username) {
		this.username = username;
	}

	public final String getPassword() {
		return password;
	}

	public final void setPassword(String password) {
		this.password = password;
	}
	
	public void setRepository(UserRepository repository) {
		this.repository = repository;
	}

	public User getModel() {
		return user;
	}

}

@Id
	@SequenceGenerator(name = "USER_GENERATOR", sequenceName = "resource_id_seq", initialValue = 1, allocationSize = 1)
	@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "USER_GENERATOR")
	private int id;

	@Embedded
	private Address address;

	@Column(nullable = false)
	private String name;

	private String password;

	@Enumerated(value = EnumType.STRING)
	private UserRole role;

	@Column(nullable = false, unique = true)
	private String login;