I've found the why!!

In my Articulo class (the one that binds the xml with the database) I have both functions defined:

• getBandeja() is the one that binds the database many to one column
• isBandeja() is an utility function that I added in the class

So, if the xml many-to-one definition says that "bandeja" is of class Articulo, why Hibernate is taking the isBandeja() function as the GetterMethodImpl if that function return a boolean??