JSF Updating Composite Component (Primefaces)

Question

I have the following UI Primefaces snippet:

Answer 1

It's because composite components inherently extend from UINamingContainer (like as <h:form>, <h:dataTable>, etc) and thus prepend the client ID of their children with own ID.

To achieve your particular functional requirement, first give your composite component a fixed ID:

<ez:growl id="growl"/>

Then embed the <p:growl> in the composite component's implementation in a plain HTML container element like <div> or <span> with the composite component's client ID as element ID:

<cc:implementation>
    <span id="#{cc.clientId}">
        <p:growl />
    </span>
</cc:implementation>

Now you can just use update=":growl" the usual way.