Probably the best way is to use JavaMail. If I'm not mistaken it's built into Java EE containers, such as the one you're using to contain your JSF code. Here's a link to the JavaMail FAQ, which specifically describes how to connect to Gmail.
It's just that I type MailUtility into NetBeans and nothing is coming up so it seems to not
be a standard package - so it's not going to be much help to anyone unless you can
provide further information about what it is, where to get it etc...
I've got e-mail sending working fine from with a Glassfish app server hooked into a
google mail account so I don't need any help myself.