Re: Generics and Polymorphism

I'm having some issues with generics and polymorphism. I thought this
was possible in Java - maybe someone can clear up what I'm doing
wrong. Basically, when I actually try to use the preference, the code
will not compile and I get the following error. How can I do what I'm
trying to do?

Here is the code that has the error:

PreferencesEnum.DERIVED_PREFERENCE.getPreference().setValue(new
String());

The error is:
The method setValue(capture#2-of ? extends Object) in the type
Preference<capture#2-of ? extends Object> is not applicable for the
arguments (String)

Thanks,
Jason

--- CLASS LISTINGS ---

I have an enum:

PreferencesEnum {
  DERIVED_PREFERENCE(new DerivedPreference());

  private final Preference<? extends Object> pref;

  private PreferencesEnum(Preference<? extends Object> pref) {
   this.pref = pref;
  }

  public Preference<? extends Object> getPreference() {
   return pref;
  }
}