Hi, I'm setting up a web application with Spring and calling a service from Bean gives me a null pointer exception error. That service is at null. I do not understand why it is, any help? Bean:
@ManagedBean(name = "alumnoBean")
@SessionScoped
public class AlumnoBean {
private static final Logger logger = Logger
.getLogger(AlumnoBean.class);
public AlumnoBean() {
System.out.println("AlumnosBean()");
}
@Autowired
private AlumnoBL serviceAlumnoBL;
public List<Alumno> getAlumnosList(){
return serviceAlumnoBL.findAllBL();
}
}
Service:
@Service
@Transactional
public class AlumnoBLImpl implements AlumnoBL {
@Autowired
private AlumnoDao dao;
@Override
@Transactional
public List<Alumno> findAllBL() {
return dao.findAllDAO();
}
DAO:
@Repository
public class AlumnoDaoImpl implements AlumnoDao {
@Autowired
private SessionFactory sessionFactory;
public List<Alumno> findAllDAO() {
return (List<Alumno>)
sessionFactory.getCurrentSession().createQuery("from Alumno").list();
}
CALL:
<ui:repeat var="list" value="#{alumnoBean.alumnosList}">
<h:inputText value="#{list.id}">
<ui:repeat>
spring-servlet.xml (com.auto is the package where beans, BL Daos and models are found):
<context:component-scan base-package="com.auto" />
ERROR: the error does not come to me when I launch the server, but when I get into the page, that is when calling the serviceAlumnoBL.findAll (); since serviceAlumnoBL is null:
GRAVE: Error Rendering View[/index.xhtml]
javax.el.ELException: /index.xhtml @17,58 value="#{alumnoBean.alumnosList}": Error reading 'alumnosList' en el tipo com.auto.bean.AlumnoBean
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:114)
at com.sun.faces.facelets.component.UIRepeat.getValue(UIRepeat.java:279)
at com.sun.faces.facelets.component.UIRepeat.getDataModel(UIRepeat.java:255)
at com.sun.faces.facelets.component.UIRepeat.setIndex(UIRepeat.java:523)
at com.sun.faces.facelets.component.UIRepeat.process(UIRepeat.java:577)
at com.sun.faces.facelets.component.UIRepeat.encodeChildren(UIRepeat.java:1110)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:456)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:133)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1099)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:670)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
Caused by: javax.el.ELException: Error reading 'alumnosList' en el tipo com.auto.bean.AlumnoBean
at javax.el.BeanELResolver.getValue(BeanELResolver.java:101)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at org.apache.el.parser.AstValue.getValue(AstValue.java:169)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:184)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
... 34 more
Caused by: javax.el.ELException: Error
at com.auto.bean.AlumnoBean.getAlumnosList(AlumnoBean.java:34)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:97)
... 39 more
Caused by: java.lang.NullPointerException
at com.auto.bean.AlumnoBean.getAlumnosList(AlumnoBean.java:31)
... 44 more
nov 20, 2017 8:28:17 PM org.apache.catalina.core.StandardWrapperValve invoke
GRAVE: El Servlet.service() para el servlet [Faces Servlet] en el contexto con ruta [/Autoescuela] lanzó la excepción [null] con causa raíz
java.lang.NullPointerException
at com.auto.bean.AlumnoBean.getAlumnosList(AlumnoBean.java:31)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:97)
at com.sun.faces.el.DemuxCompositeELResolver._getValue(DemuxCompositeELResolver.java:176)
at com.sun.faces.el.DemuxCompositeELResolver.getValue(DemuxCompositeELResolver.java:203)
at org.apache.el.parser.AstValue.getValue(AstValue.java:169)
at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:184)
at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:109)
at com.sun.faces.facelets.component.UIRepeat.getValue(UIRepeat.java:279)
at com.sun.faces.facelets.component.UIRepeat.getDataModel(UIRepeat.java:255)
at com.sun.faces.facelets.component.UIRepeat.setIndex(UIRepeat.java:523)
at com.sun.faces.facelets.component.UIRepeat.process(UIRepeat.java:577)
at com.sun.faces.facelets.component.UIRepeat.encodeChildren(UIRepeat.java:1110)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1859)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:456)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:133)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1099)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:670)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)