Difference between UIComponent getId and getClientId(FacesContext)

[Cameron Wallace McKenzie]

I'm just wondering what the difference is between the getId() and getClientId(FacesContext) method of the UIComponent?

I guess the getClientId() 'generates an id if one does not exist.' Is that the big diff? Can't we expect every component to already have an id? I'm thinking especially during the validation or conversion phase. If a UIComponent is being validated, it's already been rendered at least once, so it would have to have an id, right?

JSF 1.2 UIComponent JavaDoc

[Cameron Wallace McKenzie]

Well, when used in the validation method, if you want the <h:message for="xyz"/> tag to work, you need to use getClientId(xxx)

It seems getId() just generated the name that might be used in the tag, where the getClientId gets the fully qualified name.

 
<h:form id="rpsgameform"> 
<h:inputText id="gesture"/>
</form>   

text.getClientId --> rpsgameform:gesture
text.getId --> gesture

[Tim Holloway]

Kito Mann mentioned that fact in his JSF in Action book.