Java.lang.NullPointerException at org.primefaces.component.datatable.feature.CellEditFeature.encode ()

I am trying to create an editable data table with dynamically generated columns.

The table renders as it should and when the cells are clicked go into edit mode, but when a click is entered or when the focus leaves the cell, I get a null pointer exception on the server. The method was called onCellEdit

, but no cell value was set in the vehicle object.

• Am I doing something weird in the EL expression for an attribute value
  
  for p:inputText
  
  or p:outputText
  
  ? Should I use a different property for the attribute var
  
  on p:dataTable
  
  or p:columns
  
  ? What EL expressions are valid here?
• Am I missing something else?
• Or could this be a bug in PrimeFaces? I can see that the error occurs CellEditFeature.encode
  
  when it expects to receive CellEditor
  
  , but turns out to be null.

I've tried this with Primefaces 4.0 and 5.0 with the same result. I am using JSF 2.2, Glassfish 4.0 and Java 1.8.0_20.

If someone can help me figure out the causes of the problem, I would be very grateful. It would also be helpful to have a working example of dynamic editable data on Stack Overflow.

Bellow is a minimal example using Primefaces showcase example of dynamically created columns to which I tried to add edit and exception stack traces.

Webpage:

<p:dataTable id="cars" var="car" value="#{dtColumnsView.cars}" widgetVar="carsTable"
    editable="true" editMode="cell" >

  <p:ajax event="cellEdit" listener="#{dtColumnsView.onCellEdit}" update=":form:msgs" />

  <p:columns value="#{dtColumnsView.columns}" var="column" columnIndexVar="colIndex" 
    styleClass="ui-editable-column">

    <f:facet name="header">
      <h:outputText value="#{column.header}" />
    </f:facet>

    <p:cellEditor>
      <f:facet name="output"><h:outputText value="#{car[column.property]}" /></f:facet>
      <f:facet name="input"><p:inputText id="modelInput" value="#{car[column.property]}" /></f:facet>
    </p:cellEditor>

  </p:columns>
</p:dataTable>

      

        
        
        
      

    

Bean support:

@ManagedBean(name = "dtColumnsView")
@ViewScoped
public class ColumnsView implements Serializable {

  private static final long serialVersionUID = 1L;

  private List<ColumnModel> columns;
  private List<Car> cars;

  @ManagedProperty("#{carService}")
  private CarService service;

  @PostConstruct
  public void init() {
    cars = service.createCars(10);
    columns = Arrays.asList(
        new ColumnModel("Id", "id"), 
        new ColumnModel("Brand", "brand"), 
        new ColumnModel("Year", "year"));
  }

  public List<Car> getCars() {
    return cars;
  }

  public List<String> getBrands() {
    return service.getBrands();
  }

  public List<String> getColors() {
    return service.getColors();
  }

  public void setService(CarService service) {
    this.service = service;
  }

  public List<ColumnModel> getColumns() {
    return columns;
  }

  public void onCellEdit(CellEditEvent event) {
    Object oldValue = event.getOldValue();
    Object newValue = event.getNewValue();
    System.out.println("Cell Changed, Old: " + oldValue + ", New:" + newValue);
    if (newValue != null && !newValue.equals(oldValue)) {
      FacesMessage msg = new FacesMessage(FacesMessage.SEVERITY_INFO, "Cell Changed", "Old: " + oldValue + ", New:" + newValue);
      FacesContext.getCurrentInstance().addMessage(null, msg);
    }
  }

  public void dumpCars() {
    for (Car c : cars) System.out.println(c.brand);
  }

  static public class ColumnModel implements Serializable {

    private static final long serialVersionUID = 1L;

    private String header;
    private String property;

    public ColumnModel(String header, String property) {
      this.header = header;
      this.property = property;
    }

    public String getHeader() {
      return header;
    }

    public String getProperty() {
      return property;
    }
  }
}

      

        
        
        
      

    

Stacktrace exception:

java.lang.NullPointerException
at org.primefaces.component.datatable.feature.CellEditFeature.encode(CellEditFeature.java:54)
at org.primefaces.component.datatable.DataTableRenderer.encodeEnd(DataTableRenderer.java:76)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:924)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863)
at com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:559)
at com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:183)
at org.primefaces.component.api.UIData.visitTree(UIData.java:675)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
at javax.faces.component.UIForm.visitTree(UIForm.java:371)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
at com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:399)
at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:319)
at org.primefaces.context.PrimePartialViewContext.processPartial(PrimePartialViewContext.java:57)
at javax.faces.component.UIViewRoot.encodeChildren(UIViewRoot.java:1004)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:417)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:131)
at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:337)
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.StandardWrapper.service(StandardWrapper.java:1682)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:357)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:260)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:188)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:191)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:168)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:189)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:288)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:206)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:136)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:114)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:838)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:113)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:115)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:55)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:135)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:564)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:544)
at java.lang.Thread.run(Thread.java:745)