Exam 1z0-819 topic 1 question 188 discussion

Actual exam question from Oracle's 1z0-819

Question #: 188
Topic #: 1

Given:

class Animal { }
class Dog extends Animal { }
class Petdog extends Dog { }

and

Which two statements inserted independently on line 3 will make this code compile? (Choose two.)

A. return new House();

B. return new House();

C. return new House();

D. return new House();

E. return new House();

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Suggested Answer: BC 🗳️

by d7bb0b2 at Jan. 4, 2024, 1:25 p.m.

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d7bb0b2

1 year ago

Selected Answer: A

House<Dog>, House<Animal> , House<Object> , House(implicit object) because they are super class of Dog

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House<Object> is not allowed class Animal{} class Dog extends Animal{} class Predog extends Dog{} class House<A extends Animal> { public House<? super Dog> build(A a) { return .. } } generic method return parameter : House <? super Dog> has super type realtionship with House<Dog>, House<Animal>, House<Object>, House<> type class parameter : <A extends Animal> following types are within bounds of type-varaible A. And it allows : House<Dog>, House<Animal>, House<Predog>, House<> so intersection is House<Dog>, House<Animal>, House<>

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