Oracle Certified Associate Java Se 8 Programmer · Free Practice Question Easy
Question 52
Which is not a valid statement based on the given code?
class A {}
class B extends A {}
-
A
B b = new A(); -
B
B b = new B(); -
C
A a = new B(); -
D
A a = new A();
Reveal correct answer
Correct answer: A
Explanation
B b = new A(); -> A child class reference cannot refer to a parent class object. This will give a compilation error. A a = new B(); -> A parent class reference can refer to a child class object. This is polymorphism. B b = new B(); -> No issues at all. A a = new A(); -> No issues at all.
Discussion
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