Checking class of object

[ianyappy]

I've a following piece of code which generates an error for which I don't understand.. Would appreciate some help

public class DoggyCheck{

	public static void main(String[] args) {
		
		// Spaniel is a subclass of Dog
		Spaniel pet = new Spaniel ("Duffus");
		Dog aDogPet;

                // Check if pet is class/subclass of Dog
		if(pet instanceof Dog)
			System.out.println("We have a dog!");
		else
			System.out.println("It's definitely not a dog!");

                // Check if pet is the exact class Dog (FAIL)
		if(pet.getClass() == Dog.class)
			System.out.println("We have a dog!");
		else
			System.out.println("It's definitely not a dog!");	
	}
}

Error:
DoggyCheck.java:12: incomparable types: java.lang.Class<capture#639 of ? extends Spaniel> and java.lang.Class<Dog>
if(pet.getClass() == Dog.class)

[JosAH]

The compiler is trying to be smart, i.e. it 'knows' that pet is a Spaniel so its class can never be a Dog.class and it triumphantically starts to whine. Do that test in another method so the compiler loses track of the actual class of the object:

class Dog {
	public Dog(String name) { }
}

class Spaniel extends Dog {
	public Spaniel(String name) {
		super(name);
	}
}

public class T {
	
	private static void check(Object o) {
		if(o.getClass() == Dog.class)
			System.out.println("We have a dog!");
		else
			System.out.println("It's definitely not a dog!");	
	}
	
	public static void main(String[] args) {
		
		// Spaniel is a subclass of Dog
		Spaniel pet = new Spaniel ("Duffus");
		Dog aDogPet;

                // Check if pet is class/subclass of Dog
		if(pet instanceof Dog)
			System.out.println("We have a dog!");
		else
			System.out.println("It's definitely not a dog!");

                // Check if pet is the exact class Dog (FAIL)
		
		check(pet);
	}
}

kind regards,

Jos

[ianyappy]

Ah, ok got it. Thnx!