How to override method having Object parameter with a generic parameter?

Question

I want to override a method that has an parameter of type Object:

public void setValue(Object value) {
    // ...
}

and make that parameter to have a generic type T:

@Override
public void setValue(T value) {
    super.setValue(value);
}

How can I do this in Java?

In Eclipse I get these errors:

Multiple markers at this line
- The type parameter T is hiding the type T
- Name clash: The method setValue(T) of type TextField<T> has the 
 same erasure as setValue(Object) of type JFormattedTextField but does not 
 override it
- The method setValue(T) of type TextField<T> must override or 
 implement a supertype method

Answer 1

You can't make an overriding method accept a narrower type than the method it overrides.

If you could, the following would be possible:

class A {
    public setValue(Object o) {…}
}

class B<T> extends A {
    @Override
    public setValue(T o) {…};
}

A a = new B<String>(); // this is valid
a.setValue(new Integer(123)); // this line would compile, but make no sense at runtime