Multiple choice technology programming languages

Given: 10. abstract public class Employee { 11. protected abstract double getSalesAmount(); 12. public double getCommision() { 13. return getSalesAmount() * 0.15; 14. } 15. } 16. class Sales extends Employee { 17. // insert method here 18. } Which two methods, inserted independently at line 17, correctly complete the Sales class? (Choose two.)

  1. A. double getSalesAmount() { return 1230.45; }

  2. B. public double getSalesAmount() { return 1230.45; }

  3. C. private double getSalesAmount() { return 1230.45; }

  4. D. protected double getSalesAmount() { return 1230.45; }
Reveal answer Fill a bubble to check yourself
B,D Correct answer
Explanation

Explanation: To answer this question, we need to understand the concept of abstract classes and abstract methods in Java.

An abstract class is a class that cannot be instantiated on its own and must be subclassed. An abstract method is a method that is declared but does not have an implementation in the abstract class. Any subclass of the abstract class must provide an implementation for the abstract method.

In this code, the Employee class is an abstract class that has an abstract method named getSalesAmount(). The Sales class is a subclass of the Employee class and must provide an implementation for the getSalesAmount() method.

Option A) double getSalesAmount() { return 1230.45; } - This option is incorrect because the method needs to be declared as protected or public to provide implementation for the abstract method in the parent class.

Option B) public double getSalesAmount() { return 1230.45; } - This option is correct because it provides a public implementation for the abstract method in the parent class.

Option C) private double getSalesAmount() { return 1230.45; } - This option is incorrect because a private method cannot override a method in the parent class.

Option D) protected double getSalesAmount() { return 1230.45; } - This option is correct because it provides a protected implementation for the abstract method in the parent class.

Therefore, options B and D are the correct answers.

AI explanation

To validly override abstract double getSalesAmount(), the implementing method in Sales must keep the same signature and return type, and its access modifier must be at least as visible as the one it overrides (protected). public and protected both satisfy that (public is wider, protected matches exactly), so both compile and correctly implement the abstract method. The version with no modifier (package-private) narrows visibility below protected, and the private version isn't visible to the superclass at all — both would fail to compile as valid overrides.

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