Why can't I compare null field to a primitive [duplicate]

Question

Could you please tell me why I get a NullPointerException here?

public class N {
    private Integer n = null;
    public static void main(String... wargh) {
        N obj = new N();
        System.out.println(obj.n == 1);
    }
}

The obj.n is (obviously!) null here, so obj.n == 1 must return false - just the same way as null == 1 returns false. But it does not. Instead, it throws an exception.

Answer 1

null cannot be compared to a primitive, since a primitive can never be equal to null.

null == 1 doesn't return false - it doesn't pass compilation.

Comparing an Integer to an int requires unboxing of the Integer into an int. obj.n == 1 throws NullPointException when obj.n == null, since unboxing obj.n is equivalent to executing obj.n.intValue().