Java：方法参数中的继承类不能转换为超类

Question

I have this method with a generic class as parameter:

myMethod(Class myclass){
    Superclass superclass = myclass;
}

then I use the method by passing a child class of the Superclass

myMethod(Mychildclass.class)

Netbeans is giving me a warning that I am using generic "Class". However this works fine. If I change the method's parameter to this more specific

myMethod(Class<Superclass> myclass){
    this.superclass = myclass;
}

then I am getting an error when trying to use my method:

incompatibles types: Class<Mychildclass> cannot be converted to Class<Superclass>

So my question: Why is this not working? How can I make Netbeans happy giving me no warning and no error messages?

Answer 1

Try this instead:

private Class<? extends Superclass> superclass;

void myMethod(Class<? extends Superclass> myclass){
    this.superclass = myclass;
}

• If you use Class<Superclass> ,
  only Superclass.class is expected.

• If you use Class<? extends Superclass> Class<? extends Superclass> ,
  Superclass.class or any of its child classes are expected.