You shouldn't call action code in an attribute (property) accessor. Technically, that's known as a side-effect. In JSF it's especially important, since the accessor may get invoked more than once and at unpredictable times.
If you desire a placid life, always make your getter functions read-only and your setters should update only data and not fire off actions of their own. Leave the heavy-duty logic to action processor methods.
Bjoke: A "Bully Joke". A Statement or action made with malicious intent - unless challenged. At which point it magically transforms into "I was just funnin'" or "What's the matter, can't take a joke?"