Currently, the generated Controller classes will add a FacesMessage when
performing a create or update operation.  This FacesMessage has a sererity of
ERROR - even for a success message.

Now, the generated JSF page uses the h:messages component to capture said messages
and applies a global style of 'color:green'.

Finally, if there is an error inserting a row, nothing is propagated to the
client.  You have to go look at the server log to find out what happened, but
the JSF page, has a nice green success message at the top.

Here is how I suggest things should work.

In the Controller, have two helper methods - addSuccessMessage(String) and
addErrorMessage(String).  The addSuccessMessage(String) will add a FacesMessage
with a severity of INFO, while addErrorMessage() would basically do what the
current addMessage() implementation does.

Then, on the JSF page, leverage the fact that you can specify multiple CSS
styles for the different FacesMessage serverities (i.e. infoStyle, and errorStyle).