I have NullException on login - spring

Question

I'm trying to make a login, first time on mvc
I have this error on a proyect for university and I'm not able to see the error throw debug, I can't figure out why. When the debugger gets to line :
Empleado empleado = serviceEmpleado.correctLogin(loginFormDni, loginForm.getPassword());
on controller LoginController method checkLogin it just gives me the exception.
type Informe de Excepción
mensaje Request processing failed; nested exception is java.lang.NullPointerException
descripción El servidor encontró un error interno que hizo que no pudiera rellenar este requerimiento.
excepción
org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.NullPointerException
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:973)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
causa raíz
java.lang.NullPointerException
germanAcosta.electronicaDonPepe.controller.LoginController.checkLogin(LoginController.java:36)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:215)
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:132)
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:749)
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:689)
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:83)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:938)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
nota La traza completa de la causa de este error se encuentra en los archivos de diario de Apache Tomcat/8.0.36.
class LoginController
package germanAcosta.electronicaDonPepe.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.SessionAttributes;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;
import germanAcosta.electronicaDonPepe.DTO.Login;
import germanAcosta.electronicaDonPepe.dominio.Empleado;
import germanAcosta.electronicaDonPepe.service.ServicioException;
#Controller
//#SessionAttributes("resultado")
public class LoginController {
public ServiceEmpleado serviceEmpleado;
#RequestMapping("/login")
public String showLogin(Model model,
#ModelAttribute("resultado") String resultado, #ModelAttribute("error") String error) {
Login login = new Login();
model.addAttribute("login", login);
model.addAttribute("resultado", resultado);
model.addAttribute("error", error);
return "login";
}
#RequestMapping(value = "/login/check", method = RequestMethod.POST)
public String checkLogin(#ModelAttribute("login") Login loginForm, Model model, RedirectAttributes ra) {
try {
Integer loginFormDni = loginForm.getDni();
Empleado empleado = serviceEmpleado.correctLogin(loginFormDni, loginForm.getPassword());
model.addAttribute("loginForm", loginForm);
ra.addFlashAttribute("resultado", "El login es correcto bienvenido " + empleado.getNombre() + ".");
return "redirect:/login";
} catch (ServicioException e) {
ra.addFlashAttribute("resultado", e.getMessage());
return "redirect:/login";
} catch (Exception e) {
ra.addFlashAttribute("error", e.getCause()+ "error");
ra.addFlashAttribute("resultado", "El resultado no es el esperado");
return "redirect:/login";
}
}
}
Class ServiceEmpleado
package germanAcosta.electronicaDonPepe.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import germanAcosta.electronicaDonPepe.dominio.Empleado;
import germanAcosta.electronicaDonPepe.repository.IEmpleadoDAO;
import germanAcosta.electronicaDonPepe.service.ServicioException;
#Service
public class ServiceEmpleado {
#Autowired
private IEmpleadoDAO empleadoDAO;
public Empleado correctLogin(Integer dni, String password) throws ServicioException {
Empleado empleado = this.empleadoDAO.getById(dni);
if (empleado == null) {
throw new ServicioException("El usuario no existe");
} else if (empleado.getPassword() != password) {
throw new ServicioException("El password es incorrecto, por favor reintente nuevamente");
} else {
return empleado;
}
}
}
Login.jsp
<%# page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%# taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%# taglib prefix="sf" uri="http://www.springframework.org/tags/form"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Electronica Don Pepe</title>
</head>
<body>
<h1>login.jsp</h1>
<br>
<sf:form action="${pageContext.request.contextPath}/login/check"
method="post" commandName="login">
<table>
<tr>
<td><sf:label path="dni">Ingrese su dni</sf:label></td>
<td><sf:input path="dni" type="text" /></td>
</tr>
<tr>
<td><sf:label path="password">Ingrese su contraseña</sf:label></td>
<td><sf:input path="password" type="text" /></td>
</tr>
<tr>
<td></td>
<td><input type="submit" value="Ingresar"></td>
</tr>
</table>
</sf:form>
<c:out value="${resultado}"></c:out>
<c:out value="${loginForm.password}"></c:out>
</body>
</html>
Thanks in advance

Answer 1

In LoginController class, public ServiceEmpleado serviceEmpleado; is not autowired. It is not injected with any instance, hence it is null.
Use
#Autowired
public ServiceEmpleado serviceEmpleado;

Answer 2

I use #Autowired on my ServiceEmpleado as #Yuva suggested, but I realized that the annotation it's for an interface and not for a class. So I changed the ServiceEmpleado name to ServiceEmpleadoImpl and add an interface implementation to that class called IServiceEmpleado.
Then I add #Transactional to ServiceEmpleadoImpl and configured the bean on my Config.java
That resolved the problem. Thanks