java people..wtf is going on here.

[HAULN-SS]

class Cat { }
class Dog {
public static void main(String [] args) {
Dog d = new Dog();
System.out.println(d instanceof Cat);
}
}


Why the fuck won't that compile? you can't compare an object to some other object? do some swapping and you see that:

System.out.println(d instanceof Cat); //does not compile
System.out.println(d instanceof Dog); //compiles
if(d instanceof Cat); //also compiles

So, i know this isn't how you'd normally use this..but something funky is going on here. For some reason when it's used as an expression there it fails. WTFZO!?

[HAULN-SS]

and also

boolean b = (d instanceof Cat);
System.out.println(b);
also compiles

[white_2kgt]

lookup what instanceof compares. you are attempting to check inheritance w/o using inheritance.

instanaceof sucks, use .class for that kind of shit.

[ViPER1313]

2 classes in 1 file?

Does dog have a default constructor?

What error message are you getting exactly?

[white_2kgt]

2 classes in 1 file?

Does dog have a default constructor?

What error message are you getting exactly?

it's an example, doesn't matter, he's probably getting an Inconvertible types error.

[HAULN-SS]

the compiler inserts a default constructor automatically as long as it isn't overloaded already...

and I don't know what the exact error message is...i just noticed it when I was reading something

[HAULN-SS]

incompatable types

[Evan]

try casting to Object first and it should work

[HAULN-SS]

well, i know. I just think it's lame i can't use it in the method directly. The other ways work.

And i guess besides, i would never be doing this anyway..just thought it was interesting.

[Evan]

instanceof is when you dont know the concrete type of the object and you are using some abstract parent type to point to the object. if you are using a more concrete type, then you made a mistake. "you would never be doing this anyway" is exactly why it throws an error.
it does seem a little strange especially if coming from c++, but java babysits you more, which IMO is a good thing. no type saftey is a huge pita