Nullpointerexception error when using JSF EL

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When I add this line of code to my XHTML page:

<f:param name="pedido" value="#{pedido.id}"/>

It generates this error:

jun 04, 2015 10:59:42 AM com.sun.faces.application.view.FaceletViewHandlingStrategy handleRenderException
GRAVE: Error Rendering View[/pedidos/PesquisaPedidos.xhtml]
java.lang.NullPointerException
    at org.primefaces.renderkit.OutcomeTargetRenderer.getTargetURL(OutcomeTargetRenderer.java:95)
    at org.primefaces.component.button.ButtonRenderer.buildOnclick(ButtonRenderer.java:98)
    at org.primefaces.component.button.ButtonRenderer.encodeMarkup(ButtonRenderer.java:53)
    at org.primefaces.component.button.ButtonRenderer.encodeEnd(ButtonRenderer.java:32)
    at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:881)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1786)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782)
    at org.primefaces.component.datatable.DataTableRenderer.encodeCell(DataTableRenderer.java:808)
    at org.primefaces.component.datatable.DataTableRenderer.encodeRow(DataTableRenderer.java:773)
    at org.primefaces.component.datatable.DataTableRenderer.encodeTbody(DataTableRenderer.java:651)
    at org.primefaces.component.datatable.DataTableRenderer.encodeRegularTable(DataTableRenderer.java:234)
    at org.primefaces.component.datatable.DataTableRenderer.encodeMarkup(DataTableRenderer.java:196)
    at org.primefaces.component.datatable.DataTableRenderer.encodeEnd(DataTableRenderer.java:82)
    at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:881)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1786)
    at javax.faces.render.Renderer.encodeChildren(Renderer.java:168)
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:851)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1779)
    at com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:513)
    at com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:183)
    at javax.faces.component.UIForm.visitTree(UIForm.java:381)
    at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
    at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
    at com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:378)
    at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:298)
    at javax.faces.context.PartialViewContextWrapper.processPartial(PartialViewContextWrapper.java:183)
    at javax.faces.context.PartialViewContextWrapper.processPartial(PartialViewContextWrapper.java:183)
    at javax.faces.component.UIViewRoot.encodeChildren(UIViewRoot.java:973)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1779)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:413)
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:124)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:286)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:286)
    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:139)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1086)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:659)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1558)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1515)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)

2015-06-04 10:59:42,128 ERROR [com.algaworks.pedidovenda.util.jsf.JsfExceptionHandler] Erro de sistema: null
java.lang.NullPointerException
    at org.primefaces.renderkit.OutcomeTargetRenderer.getTargetURL(OutcomeTargetRenderer.java:95)
    at org.primefaces.component.button.ButtonRenderer.buildOnclick(ButtonRenderer.java:98)
    at org.primefaces.component.button.ButtonRenderer.encodeMarkup(ButtonRenderer.java:53)
    at org.primefaces.component.button.ButtonRenderer.encodeEnd(ButtonRenderer.java:32)
    at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:881)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1786)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1782)
    at org.primefaces.component.datatable.DataTableRenderer.encodeCell(DataTableRenderer.java:808)
    at org.primefaces.component.datatable.DataTableRenderer.encodeRow(DataTableRenderer.java:773)
    at org.primefaces.component.datatable.DataTableRenderer.encodeTbody(DataTableRenderer.java:651)
    at org.primefaces.component.datatable.DataTableRenderer.encodeRegularTable(DataTableRenderer.java:234)
    at org.primefaces.component.datatable.DataTableRenderer.encodeMarkup(DataTableRenderer.java:196)
    at org.primefaces.component.datatable.DataTableRenderer.encodeEnd(DataTableRenderer.java:82)
    at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:881)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1786)
    at javax.faces.render.Renderer.encodeChildren(Renderer.java:168)
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:851)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1779)
    at com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:513)
    at com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:183)
    at javax.faces.component.UIForm.visitTree(UIForm.java:381)
    at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
    at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
    at com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:378)
    at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:298)
    at javax.faces.context.PartialViewContextWrapper.processPartial(PartialViewContextWrapper.java:183)
    at javax.faces.context.PartialViewContextWrapper.processPartial(PartialViewContextWrapper.java:183)
    at javax.faces.component.UIViewRoot.encodeChildren(UIViewRoot.java:973)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1779)
    at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:413)
    at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:124)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:286)
    at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:286)
    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:139)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1086)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:659)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1558)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1515)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)

Could someone explain to me the mistake?

java jsf java-ee jsf-2.2 nullpointerexception

  • Where are you adding the <f:param>?

2 answers

1

The explanation is simple. In your code, you have #{pedido.id}, and the pedido is null. The result of this is that the NullPointerException is released.

  • Your answer was good, but even knowing that I still can’t find a way to fix the problem.

0

You’re probably using this syntax inside a datatable , with it there is an attribute called var containing the current object used.

You must use the attribute value var as an attribute value value of your attribute

<f:attribute name="pedido" value="#{pedido}/>

And in your MB constructor it should be initialized initially. Otherwise it will occur NullPointerException again.

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