Java – override methods and then face problems

When the overlay method then faces a problem:

public interface IProduct {
    public void sendMessage(Object object);
}


@Service
public class ProductManagere implements IProduct{

    @Override
    public void sendMessage(Product product) {
        // Added logic
    }
}

But below the exception:

I don't understand why this exception is thrown I want product to be a subtype of object, so it won't throw an exception

Solution

In Java, overriding the covariance of parameters is not allowed

Therefore, you must keep object as a parameter in a subclass (which may not be what you want) or make the interface a general interface, for example:

public interface IProduct<T> {
    void sendMessage(T object);
}

And subclasses:

@Service
public class ProductManagere implements IProduct<Product>{

    @Override
    public void sendMessage(Product product) {
        // Added logic
    }
}