Exam 1z0-819 topic 1 question 202 discussion

Actual exam question from Oracle's 1z0-819

Question #: 202
Topic #: 1

Given:

and

public class Bar extends Foo { ... }

Which two statements are true if the method is added to Bar? (Choose two.)

A. public Collection foo (Collection arg) { ... } overrides Foo.foo.
B. public Collection foo(Stream arg) { ... } overloads Foo.foo.
C. public Iterable foo{Collection arg) { ... } overrides Foo.foo.
D. public Collection bar(Collection arg) { ... } overloads Foo.foo.
E. public List foo (Collection arg) { ... } overrides Foo.foo.
F. public Collection foo(Collection arg) { ... } overloads Foo.foo.

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Suggested Answer: BE 🗳️

by d7bb0b2 at Jan. 4, 2024, 3:41 p.m.

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ASPushkin

1 year ago

answer : ABE The bytecode after compilation with type erasure contains only normal classes, interfaces and methods, ensuring that no new types are produced. public Collection foo(Collection arg) {...} A) correct B) correct different arguments so this overloads C) not correct Iterable is an interface so it is not a covariant type E) correct return type is a covariant to Collection F) not correct this is overrides see A

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d7bb0b2

1 year ago

that is ok a : is override b : is overload e: is override (List is a subtype of Collection, rule of override )

upvoted 1 times

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d7bb0b2

1 year ago

3 are valid: A: overload B: overrride C: overload

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d7bb0b2

1 year ago

B: is overload sorry

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