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Editorial Team
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Asked: 2026-06-16T23:11:19+00:00

Used this StackOverflow answer to try an implement a submitless form. The page consists

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Used this StackOverflow answer to try an implement a submitless form. The page consists of a selectomenu control and a table. On change of the selection I wish to refresh the table body. The page loads without issues, but when the selection is made I get the following error occurs:

10:22:48,241 ERROR [[FacesServlet]] Servlet.service() for servlet FacesServlet threw exception: java.lang.NullPointerException
    at com.sun.faces.context.PartialViewContextImpl.createPartialResponseWriter(PartialViewContextImpl.java:441) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at com.sun.faces.context.PartialViewContextImpl.access$300(PartialViewContextImpl.java:71) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at com.sun.faces.context.PartialViewContextImpl$DelayedInitPartialResponseWriter.getWrapped(PartialViewContextImpl.java:582) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at javax.faces.context.PartialResponseWriter.startDocument(PartialResponseWriter.java:115) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at com.sun.faces.context.AjaxExceptionHandlerImpl.handlePartialResponseError(AjaxExceptionHandlerImpl.java:199) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at com.sun.faces.context.AjaxExceptionHandlerImpl.handle(AjaxExceptionHandlerImpl.java:123) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:119) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at com.sun.faces.lifecycle.RestoreViewPhase.doPhase(RestoreViewPhase.java:116) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118) [jsf-impl-2.1.7-jbossorg-2.jar:]
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:329) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.13.Final.jar:]
    at org.jboss.as.jpa.interceptor.WebNonTxEmCloserValve.invoke(WebNonTxEmCloserValve.java:50) [jboss-as-jpa-7.1.1.Final.jar:7.1.1.Final]
    at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:153) [jboss-as-web-7.1.1.Final.jar:7.1.1.Final]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:505) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.ajp.AjpProtocol$AjpConnectionHandler.process(AjpProtocol.java:445) [jbossweb-7.0.13.Final.jar:]
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930) [jbossweb-7.0.13.Final.jar:]
    at java.lang.Thread.run(Thread.java:636) [rt.jar:1.6.0_18]

I’m using JBoss-AS-7.1.1, and the selectonmenu looks like this:

<h:selectOneMenu id="ship"
             value="#{shipManager.current}">
    <f:selectItems value="#{shipManager.list}"
               var="ship"
               itemValue="#{ship}"
               itemLabel="#{ship.name}" />
    <f:ajax listener="#{shipManager.changeShip}" />
</h:selectOneMenu>

If I remove the ajax component then no issues although (of course) the shipManager is not updated.

Once I have the selection made I would then like to add the renderer part to refresh my table body.

Many thanks for any help given.

Steve

As requested here is my XHTML code:

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:f="http://java.sun.com/jsf/core"
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:ui="http://java.sun.com/jsf/facelets">

  <h:head>
    <title>Voyage Cruises</title>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <link type="text/css" rel="stylesheet" media="all" href="/css/screen.css"/>
    <link type="text/css" rel="stylesheet" media="all" href="/css/cruise.css"/>
    <script src="http://open.mapquestapi.com/sdk/js/v7.0.s/mqa.toolkit.js"></script> 
    <script src="js/map.js" ></script>
    <script src="js/cruise.js" ></script>
  </h:head>

  <h:body>
    <div id="page">
      <div id="float-map">
    <div id="map"></div>
      </div>

      <h:form id="ship-form">

    <div id="ship-controls">
      <div class="float-ctrls">
        <a href="/ports.html" title="Find Ports"><img src="/images/action_search.png" alt="Find Ports"/></a>
      </div>
      <div>
        <span id="ship-selector" >
          <h:selectOneMenu id="ship"
                   value="#{shipManager.current}">
        <f:selectItems value="#{shipManager.list}"
                   var="ship"
                   itemValue="#{ship}"
                   itemLabel="#{ship.name}" />
        <f:ajax execute="ship" render="@form" listener="#{shipManager.changeShip}" />
          </h:selectOneMenu> 
        </span>
        <select id="month" />
        <select id="year" />
        <br />
        <span class="input-container"><b>Tonnage:</b><input id="tonnage" type="text" size="6" value="30,277" /></span>
        <span class="input-container"><b>Audit Time:</b><input id="audit" type="text" size="2" value="6" /></span>
        <span class="input-container"><b>Fleet:</b><input id="fleet" type="text" size="20" value="P&amp;O" /></span>
      </div>
    </div>

    <table class="cruise">
      <thead>
        <tr>
          <th class="date">Date</th>
          <th class="port">Port</th>
          <th class="arrive">Arrive</th>
          <th class="depart">Depart</th>
        </tr>
      </thead>
      <tbody>
        <ui:repeat var="cruise"
               value="#{cruiseManager.list}" 
               varStatus="table">
          <tr class="#{table.even ? 'even' : 'odd'}">
        <td class="date">
          <h:outputFormat value="{0, date,d MMM}">
            <f:param value="#{cruise.date}" />
          </h:outputFormat>
        </td>
        <h:panelGroup rendered="#{null != cruise.port}">
          <td class="port">#{cruise.port.name}</td>
          <td class="arrive">
            <h:outputFormat rendered="#{null != cruise.arrival}"
                    styleClass="#{cruise.arrivalEstimated ? 'est-time' : 'act-time'}"
                    value="{0, date,HH:mm}">
              <f:param value="#{cruise.arrival}" />
            </h:outputFormat>
          </td>
          <td class="depart">
            <h:outputFormat rendered="#{null != cruise.departure}"
                    styleClass="#{cruise.departureEstimated ? 'est-time' : 'act-time'}"
                    value="{0, date,HH:mm}">
              <f:param value="#{cruise.departure}" />
            </h:outputFormat>
          </td>
        </h:panelGroup>
        <h:panelGroup rendered="#{null == cruise.port}">
          <td class="at-sea" colspan="3">At Sea</td>
        </h:panelGroup>
          </tr>
        </ui:repeat>
      </tbody>
    </table>

      </h:form>
    </div>
  </h:body>
</html>

And the ShipManager:

package com.nutrastat.voyager.web;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

import javax.ejb.EJB;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
import javax.faces.event.AjaxBehaviorEvent;

import com.nutrastat.voyager.db.HarbourMasterLocal;
import com.nutrastat.voyager.db.ShipEntity;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@ManagedBean
@ViewScoped
public class ShipManager 
    implements Serializable {

    static final long serialVersionUID = -3017226836104715117L;

    private transient final Logger log;

    private ShipEntity currentShip;

    @EJB
    private HarbourMasterLocal harbourMaster;

    public ShipManager() {
    log = LoggerFactory.getLogger(getClass());
    }

    public ShipEntity getCurrent() {
    if (log.isInfoEnabled())
        log.info("getCurrent(): " + currentShip);
    return currentShip;
    }

    public void setCurrent(ShipEntity ship) {
    if (log.isInfoEnabled())
        log.info("setCurrent(" + currentShip + "): " + ship);
    currentShip = ship;
    }

    public void changeShip(AjaxBehaviorEvent evt) {
    if (log.isInfoEnabled())
        log.info("Ship now: " + currentShip);
    }

    public List<ShipEntity> getList() {
    try {
        return harbourMaster.listShips();

    } catch (Exception cause) {
        log.error("Getting the list of ships", cause);
        return new ArrayList<ShipEntity>(0);
    }
    }
}
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1 Answer

  1. Editorial Team

    Your stack trace looks incomplete in that it doesn’t actually refer to your code(which is where I’d expect the npe be thrown). That notwithstanding, your select menu doesn’t have a converter, so any other problems aside, your form would probably still not save or register the selection

    1. Implement a JSF converter and declare it on that selectonemenu. This is mandatory when a select type component needs to select and save complex POJO types You can look at this example

    2. Try to get rid of that gigantic <h:form/> in your markup. There are too many other components in that form that could be causing you problems. Break the components into smaller chunks in separate forms

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