FacesContext.getCurrentInstance() returns null within request handled by FacesServlet(?)

Question

I have a Facelet that has two <h:forms>. The command link in one form executes without a problem. The command link in the other form does not work: a NullPointerException is thrown because FacesContext.getCurrentInstance() is returning null. It appears to me that the request goes through FacesServlet so it doesn't make sense that FacesContext.getCurrentInstance() would return null.

Here's the XHTML:

<h:form>
    <h:commandLink action="#{localeManager.setLanguage('en')}">English</h:commandLink>
</h:form>

The resulting HTML is here:

<form id="j_idt20" name="j_idt20" method="post" action="/Patrac/faces/academicyear.xhtml" enctype="application/x-www-form-urlencoded">
    <input type="hidden" name="j_idt20" value="j_idt20" />
    <script type="text/javascript" src="/Patrac/faces/javax.faces.resource/jsf.js?ln=javax.faces&amp;stage=Development"></script>
    <a href="#" onclick="mojarra.jsfcljs(document.getElementById('j_idt20'),{'j_idt20:j_idt22':'j_idt20:j_idt22'},'');return false">English</a>
    <input type="hidden" name="javax.faces.ViewState" id="javax.faces.ViewState" value="-3103232499387158697:-8681635922139458233" autocomplete="off" />
</form>

Here is the LocaleManager:

@Named
@SessionScoped
public class LocaleManager implements Serializable
{
...
    public void setLanguage(String language)
    {
        this.locale = new Locale(language);
        FacesContext fc = FacesContext.getCurrentInstance();


        UIViewRoot uivr = fc.getViewRoot(); <===== NullPointerException

        uivr.setLocale(locale);
    }
}

And here's the stack trace:

16:35:31,697 WARNING [javax.enterprise.resource.webcontainer.jsf.lifecycle] (http--127.0.0.1-8443-4) #{localeManager.setLanguage('en')}: java.lang.NullPointerException: javax.faces.FacesException: #{localeManager.setLanguage('en')}: java.lang.NullPointerException
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:118) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at javax.faces.component.UICommand.broadcast(UICommand.java:315) [jboss-jsf-api_2.1_spec-2.0.0.Beta1.jar:2.0.0.Beta1]
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794) [jboss-jsf-api_2.1_spec-2.0.0.Beta1.jar:2.0.0.Beta1]
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259) [jboss-jsf-api_2.1_spec-2.0.0.Beta1.jar:2.0.0.Beta1]
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593) [jboss-jsf-api_2.1_spec-2.0.0.Beta1.jar:2.0.0.Beta1]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:329) [jbossweb-7.0.7.Final.jar:]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.7.Final.jar:]
    at org.jboss.weld.servlet.ConversationPropagationFilter.doFilter(ConversationPropagationFilter.java:62) [weld-core-1.1.4.Final.jar:2011-11-22 20:01]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:280) [jbossweb-7.0.7.Final.jar:]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.7.Final.jar:]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [jbossweb-7.0.7.Final.jar:]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.7.Final.jar:]
    at org.jboss.as.jpa.interceptor.WebNonTxEmCloserValve.invoke(WebNonTxEmCloserValve.java:50) [jboss-as-jpa-7.1.0.CR1b.jar:7.1.0.CR1b]
    at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:151) [jboss-as-web-7.1.0.CR1b.jar:7.1.0.CR1b]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.7.Final.jar:]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.7.Final.jar:]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.7.Final.jar:]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:362) [jbossweb-7.0.7.Final.jar:]
    at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:897) [jbossweb-7.0.7.Final.jar:]
    at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:626) [jbossweb-7.0.7.Final.jar:]
    at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:2033) [jbossweb-7.0.7.Final.jar:]
    at java.lang.Thread.run(Thread.java:722) [:1.7.0_02]
Caused by: javax.faces.el.EvaluationException: java.lang.NullPointerException
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:102) [jboss-jsf-api_2.1_spec-2.0.0.Beta1.jar:2.0.0.Beta1]
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    ... 24 more
Caused by: java.lang.NullPointerException
    at com.patrac.controller.LocaleManager.setLanguage(LocaleManager.java:38) [Patrac-ejb-1.0-SNAPSHOT.jar:]
    at com.patrac.controller.LocaleManager$Proxy$_$$_WeldClientProxy.setLanguage(LocaleManager$Proxy$_$$_WeldClientProxy.java) [Patrac-ejb-1.0-SNAPSHOT.jar:]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.7.0_02]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) [:1.7.0_02]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [:1.7.0_02]
    at java.lang.reflect.Method.invoke(Method.java:601) [:1.7.0_02]
    at org.apache.el.parser.AstValue.invoke(AstValue.java:262) [jbossweb-7.0.7.Final.jar:]
    at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:278) [jbossweb-7.0.7.Final.jar:]
    at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:39) [weld-core-1.1.4.Final.jar:2011-11-22 20:01]
    at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:50) [weld-core-1.1.4.Final.jar:2011-11-22 20:01]
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105) [jsf-impl-2.1.5-jbossorg-1.jar:2.1.5-SNAPSHOT]
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:88) [jboss-jsf-api_2.1_spec-2.0.0.Beta1.jar:2.0.0.Beta1]
    ... 25 more

Taking a look at this answer to a similar question my first thought was that the request was not going through FacesServlet. But looking at form action field in the generated HTML and the stack trace, above, it looks to me like the request is going through FacesServlet.

Any ideas on this? What am I not getting?

Answer 1

The problem was that I was invoking FacesContext.getCurrentInstance() from the EJB tier. This is why it worked when deployed as a WAR, but not as an EAR. I was very low on the Java EE learning curve at the time :-)