The following bean seems to load fine upon startup and when facelets are loaded, as evidenced by the log:

@ManagedBean(eager=true)
@ApplicationScoped
public class EnumConfig {

    @PostConstruct
    public void init() {

        System.out.println("Testing 123...");
        FacesContext.getCurrentInstance().getApplication().addELContextListener (
            new ELContextListener() {
         
                @Override
                public void contextCreated(ELContextEvent event) {
             
                    System.out.println("Testing 456...");
                    ImportHandler importHandler = event.getELContext().getImportHandler();
                    importHandler.importClass("foo.bar.business.model.enumeration.YesOrNo");
                    Class<?> clazz = importHandler.resolveClass("YesOrNo");
                    System.out.println("class = " + clazz);
                }
            }
        );
    }
}

21:26:48,703 INFO [stdout] (MSC service thread 1-4) Testing 123...
21:39:11,976 INFO [stdout] (default task-9) Testing 456...
21:39:11,976 INFO [stdout] (default task-18) class = null

YesOrNo is not imported because clazz == null in EnumConfig code snippet. This is a problem.  And as expected the value expression can't resolve YesOrNo#values(). The select list is rendered empty, with no YesOrNo values.

<f:selectItems
    value="#{YesOrNo.values()}"
    var="yesOrNo"
    itemValue="#{yesOrNo}"
    itemLabel="#{yesOrNo.name()}"/>

I set a breakpoint after ImportHandler#importClass and I can see that classNameMap is properly populated:

importHandler = {javax.el.ImportHandler@17821}

    classNameMap = {java.util.HashMap@17822} size = 1

        [0] = {java.util.HashMap$Node@17830}"YesOrNo" -> "foo.bar.business.model.enumeration.YesOrNo"

    classMap = {java.util.HashMap@17823} size = 0

    staticNameMap = {java.util.HashMap@17824} size = 0

    notAClass = {java.util.HashSet@17825} size = 0

    packages = {java.util.ArrayList@17826} size = 1

        [0] = {java.lang.String@17286}"java.lang"

            value = {char[9]@17287}

            hash = -888658374

 

So, classNameMap is populated correctly but the import handler cannot resolve the class.  The JavaDoc for ImportHandler#resolveClass() indicates I am using it correctly (without package name).  Why is import handler unable to resolve the class?

FYI, using <o:importConstants> of OmniFaces works just fine.

<o:importConstants type="foo.bar.business.model.enumeration.YesOrNo"/>

What can I do to further troubleshoot this problem?