Setting null values to view.attributes

Question

Hi all, I am getting following NPE posting form to server. Below I m writing snippet of code which causes the issue:
SEVERE: value is null for a not available property: test
java.lang.NullPointerException: value is null for a not available property: test
     at javax.faces.component._ComponentAttributesMap.put(_ComponentAttributesMap.java:303)
     at javax.el.MapELResolver.setValue(MapELResolver.java:90)
     at javax.el.CompositeELResolver.setValue(CompositeELResolver.java:69)
     at org.apache.myfaces.el.unified.resolver.FacesCompositeELResolver.setValue(FacesCompositeELResolver.java:180)
     at org.apache.el.parser.AstValue.setValue(AstValue.java:158)
     at org.apache.el.ValueExpressionImpl.setValue(ValueExpressionImpl.java:249)
     at org.apache.jasper.el.JspValueExpression.setValue(JspValueExpression.java:85)
     at javax.faces.component.UIInput.updateModel(UIInput.java:287)
     at javax.faces.component.UIInput.processUpdates(UIInput.java:214)
     at javax.faces.component.UIForm.processUpdates(UIForm.java:99)
     at org.ajax4jsf.component.AjaxViewRoot$2.invokeContextCallback(AjaxViewRoot.java:424)
     at org.ajax4jsf.component.AjaxViewRoot.processPhase(AjaxViewRoot.java:240)
     at org.ajax4jsf.component.AjaxViewRoot.processUpdates(AjaxViewRoot.java:440)
     at org.apache.myfaces.lifecycle.UpdateModelValuesExecutor.execute(UpdateModelValuesExecutor.java:33)
     at org.apache.myfaces.lifecycle.LifecycleImpl.executePhase(LifecycleImpl.java:103)
     at org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:76)
     at javax.faces.webapp.FacesServlet.service(FacesServlet.java:151)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
     at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:341)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
     at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:206)
     at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:290)
     at org.ajax4jsf.webapp.BaseFilter.processUploadsAndHandleRequest(BaseFilter.java:388)
     at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:515)
     at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
     at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
     at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
     at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
     at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
     at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
     at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
     at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
     at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:852)
     at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
     at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
     at java.lang.Thread.run(Unknown Source)My Jsp Page code snippet:
<t:selectOneMenu value="#{view.attributes['test']}">
     <f:selectItems value="#{myController.listValues}"/>
</t:selectOneMenu>MyController.java bean property:
public List<SelectItem> getListValues() {
          listValues.clear();
          SelectItem si = new SelectItem("", "-Select-");
          SelectItem si2 = new SelectItem("1", "1");
          SelectItem si3 = new SelectItem("2", "2");
          listValues.add(si);
          listValues.add(si2);
          listValues.add(si3);
          return listValues;
     }When user selects nothing, I need to set NULL value for this drop down. Kindly suggest if there is any other way or best practice to do the same.I am using Myfaces 1.2.5 for JSF 1.2. This thing was working fine in Myfaces 1.1.5 for JSF 1.1.Any suggestions?

Answer 1

Give this a try:
<t:selectOneMenu value="#{view.attributes['test']}">
        <f:selectItem itemLabel="-Select-" />
     <f:selectItems value="#{myController.listValues}"/>
</t:selectOneMenu>
public List<SelectItem> getListValues() {
          listValues.clear();
          listValues.add(new SelectItem("1", "1");
          listValues.add(new SelectItem("2", "2");
          return listValues;
     }Note: I cleaned up your getListValue() a bit - most of the changes are cosmetic except for removing you '-Select-' selectItem. Also, why do you use a class level variable if you are generating it on each call? Either generate the list on constructor call (or when needed) and just return it from getListValues(), or simply use a local variable.