If I'm writting a bean - and I mean just a plain old Java Bean not an EJB or
anything like that - is there any merit to seperating the interface out of
the class? I do this with pretty much every other kind of class I write but
Beans...

l-EE wrote:

If I'm writting a bean - and I mean just a plain old Java Bean not an EJB or
anything like that - is there any merit to seperating the interface out of
the class? I do this with pretty much every other kind of class I write but
Beans...

Just like any class, if you separate out the interface you can have
other developers implement the interface in order to extend your
JavaBean ideas. Of course you might also want to provide an empty
implementation of the interface as a convenience class of those who just
want to extend the interface with just a subset of changes from the default.

Another advantage of separating out an interface, as a common idea, is
that you can have collections of the interface quite easily, and this
sort of collection will extend to other developers building JavaBeans
from your interface.