Given: package a; public abstract class Animal { protected abstract void walk(); } package b; public abstract class Human extends Animal { // line 1 } Which two lines inserted in line 1 will allow…

Question

Options

• Aprotected void walk(){}
• Bvoid walk(){}
• Cpublic void walk(){}
• Dprivate void walk(){}
• Epublic abstract void walk();

• A
  77% (17)
• B
  14% (3)
• C
  5% (1)
• D
  5% (1)

Explanation

A works because Human is also abstract, so it can provide a concrete implementation of walk() - and since walk() is protected in Animal, the overriding method must be protected or more visible (not less). E works because an abstract class is allowed to re-declare an abstract method with the same or broader access modifier, effectively forwarding the obligation to a concrete subclass.

B fails because void walk(){} uses package-private access, which is narrower than protected - Java prohibits reducing visibility when overriding. D fails for the same reason: private is even more restrictive and cannot override an inherited method at all. C (public void walk(){}) is actually valid Java, but it is not listed as a correct answer here - re-read the question: the exam specifically asks which two compile, and only A and E are among the intended pair (note: C would also compile in a real JVM, so this may be a flawed question, but within the exam's logic A and E are the expected picks).

Memory tip: Think "you can only open up access, never lock it down" when overriding - a protected parent method can be overridden as protected or public, but never package-private or private. Abstract classes get a free pass to re-declare abstract methods without providing a body.

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