No, you can't put
Java code in faces-config. You can, however use EL. So as long as you have the bean in question mapped under a name in a context that the EL processor can use, you can do it. However, I don't know anything that's available off the shelf.
If you are using Spring and have added the Spring EL properties resolver to the faces-config, you can let Spring construct a bean based on those properties and inject it into
JSF.