Re: Yet another generics question: Needs unchecked conversion to conform to ...
Thanks for your replies,
Daniel Pitts a =E9crit :
*Why* do you need to use reflection? I've found that in most
circumstances, you don't need to use it, even if you *think* you do.
I'll explain in an upcoming separate message.
Moving forward, assuming that you do indeed need to do it this way...
what is the exact warning you get? Can you post an sscce
<http://physci.org/codes/sscce/> that allows us to reproduce the
problem?
The exat warning is:
Type safety: The expression of type capture-of ? extends
Generics.BeanFactory needs unchecked conversion to conform to
Generics.BeanFactory<? extends Generics.Bean>
The "ssce" (thank you for the info on this acronym) was there in the
first message: The "Generics" class compiles as is without any
dependanies, and the warning shows up in Eclipse (I did not try on any
other compiler). Here it is again with a slight modification in the
return type of the createFactory2 method :
public class Generics {
public BeanFactory createFactory1(String beanClass) throws Exception{
Class<?> bc = Class.forName(beanClass);
Class<? extends BeanFactory> bfc =
bc.asSubclass(BeanFactory.class);
Constructor<? extends BeanFactory> cstr =
bfc.getConstructor(new Class[]{});
return cstr.newInstance(new Object[]{});
}
public BeanFactory<? extends Bean> createFactory2(String beanClass)
throws Exception{
Class<?> bc = Class.forName(beanClass);
Class<? extends BeanFactory> bfc =
bc.asSubclass(BeanFactory.class);
Constructor<? extends BeanFactory> cstr =
bfc.getConstructor(new Class[]{});
// The following line causes a warning
return cstr.newInstance(new Object[]{});
}
public class BeanFactory<T extends Bean>{
}
public class Bean{
}
}