How to use abstract class as CDI managed bean in JSF view - jsf

Question

Can I use abstract class as CDI managed bean in JSF view? I want set or override attribute in derived class and use it in JSF page of parent abstract class. Derived view to set context which template parent view must show as common part all childs .
I heard that i can use abstract class with #Named annotation in JSF view, but i get error
Target Unreachable, identifier 'viewModel' resolved to null
If I change the abstract class to a typical class then its work. May be using abstract class in JSF view impossible?
ViewModel.java
#Named
#ConversationScoped
#Inherited
#Documented
#Stereotype
#Target({ TYPE })
#Retention(RUNTIME)
public abstract class ViewModel {
private String foo;
public void setFoo(String foo) {
this.foo = foo;
}
public String getFoo() {
return foo;
}
abstract void bar();
}
DerivedViewModel.java
#Named
#ConversationScoped
#Inherited
#Documented
#Stereotype
#Target({ TYPE })
#Retention(RUNTIME)
public class DerivedViewModel extends ViewModel {
public void init() {
this.setFoo("Foo");
}
#Override
void bar() {;}
}
View.xhtml
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://xmlns.jcp.org/jsf/html" xmlns:f="http://xmlns.jcp.org/jsf/core"
xmlns:ui="http://xmlns.jcp.org/jsf/facelets" xmlns:c="http://xmlns.jcp.org/jsp/jstl/core"
xmlns:fn="http://xmlns.jcp.org/jsp/jstl/functions" xmlns:pt="http://xmlns.jcp.org/jsf/passthrough"
xmlns:p="http://primefaces.org/ui" xmlns:pe="http://primefaces.org/ui/extensions"
xmlns:sys="http://argustelecom.ru/system" xmlns:o="http://omnifaces.org/ui">
<ui:param name="viewModel" value="#{viewModel}" />
<ui:define name="body">
<h:outputText value="#{viewModel.foo}" />
<ui:insert name="derived" />
</ui:define>
</ui:composition>
DerivedView.xhtml
<ui:composition template="View.xhtml" xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://xmlns.jcp.org/jsf/html" xmlns:f="http://xmlns.jcp.org/jsf/core"
xmlns:ui="http://xmlns.jcp.org/jsf/facelets" xmlns:c="http://xmlns.jcp.org/jsp/jstl/core"
xmlns:fn="http://xmlns.jcp.org/jsp/jstl/functions" xmlns:pt="http://xmlns.jcp.org/jsf/passthrough"
xmlns:p="http://primefaces.org/ui" xmlns:pe="http://primefaces.org/ui/extensions"
xmlns:sys="http://argustelecom.ru/system" xmlns:o="http://omnifaces.org/ui">
<ui:param name="viewModel" value="#{derivedViewModel}" />
<ui:define name="metadata">
<f:metadata>
<f:viewAction action="#{derivedViewModel.init()}"/>
</f:metadata>
</ui:define>
<ui:define name="derived">
blablabla
</ui:define>
</ui:composition>

Answer 1

Forget EL or JSF. Think in terms of OO . Can you do this call.
viewModel.foo
Answer is no because it is abstract and viewModel can not exist as an instance of the abstract class ViewModel. For the exact same reason you can not use it in EL.