For this I intend <h:message>(or an analogue of PrimeFaces <p:message>). Or, in your case, it might be better <h:messages>(or <p:messages>).
public void submit() {
if (fail) {
FacesContext.getCurrentInstance().addMessage(null,
new FacesMessage(FacesMessage.SEVERITY_ERROR, "Fail", null));
}
}
with
<h:messages id="messages" />
<p:commandLink process="@form" action="#{bean.submit}" update="messages something" />
, Validator . ValidatorException, . - .