Multiple choice technology programming languages

Given: 1. class Example { 2. public static void main(String[] args) { 3. Short s = 15; 4. Boolean b; 5. // insert code here 6. } 7. } Which, inserted independently at line 5, will compile? (Choose all that apply.)

  1. b = (Number instanceof s);

  2. b = (s instanceof Short);

  3. b = s.instanceof(Short);

  4. b = (s instanceof Number);

  5. b = s.instanceof(Object);

  6. b = (s instanceof String);
Reveal answer Fill a bubble to check yourself
B,D Correct answer
Explanation

Short is a wrapper class and inherits from Number. Options B and D are correct: s instanceof Short checks if s is a Short instance (true), and s instanceof Number checks if s is a Number instance (also true, since Short extends Number). Option A has reversed instanceof syntax. Options C, E use dot notation instead of instanceof keyword.

AI explanation

To determine which options will compile when inserted at line 5, let's go through each option:

Option A) b = (Number instanceof s); This option will not compile because the syntax is incorrect. The correct syntax for the instanceof operator is variable instanceof Class.

Option B) b = (s instanceof Short); This option will compile because it uses the correct syntax for the instanceof operator. It checks if the variable s is an instance of the Short class.

Option C) b = s.instanceof(Short); This option will not compile because the syntax is incorrect. The instanceof operator should be used with the variable on the left side.

Option D) b = (s instanceof Number); This option will compile because it uses the correct syntax for the instanceof operator. It checks if the variable s is an instance of the Number class.

Option E) b = s.instanceof(Object); This option will compile because it uses the correct syntax for the instanceof operator. It checks if the variable s is an instance of the Object class.

Option F) b = (s instanceof String); This option will not compile because it uses the incorrect class name. The variable s is declared as a Short, so it cannot be an instance of the String class.

Therefore, the options that will compile when inserted at line 5 are B) b = (s instanceof Short); and D) b = (s instanceof Number);.

Keep practicing — related questions