Given: `` public class Product { public double applyDiscount(double price) { assert (price > 0); // line n1 return price * 0.50; } public static void main(String[] args) { Product p = new Product()…

Question

public class Product {
 public double applyDiscount(double price) {
 assert (price > 0); // line n1
 return price * 0.50;
 }

 public static void main(String[] args) {
 Product p = new Product();
 double newPrice =
 p.applyDiscount(Double.parseDouble(args[0]));
 System.out.println("New Price: " + newPrice);
 }
}

Options

• AAn AssertionError is thrown.
• BA compilation error occurs at line n1.
• CNew Price: 0.0
• DA NumberFormatException is thrown at run time.

• A
  11% (2)
• B
  5% (1)
• C
  79% (15)
• D
  5% (1)

Explanation

Option C is correct because Java assertions are disabled by default at runtime - you must explicitly enable them with the -ea (enable assertions) JVM flag. Since the command is java Product 0 without -ea, the assert statement on line n1 is completely ignored, price remains 0.0, and the calculation 0.0 * 0.50 yields 0.0, producing New Price: 0.0.

Why the distractors are wrong:

• A is wrong because even though 0 > 0 is false, the AssertionError is never triggered - assertions are off unless you run java -ea Product 0.
• B is wrong because assert is valid Java syntax (introduced in Java 1.4); there is no compilation error.
• D is wrong because Double.parseDouble("0") is perfectly valid and returns 0.0; a NumberFormatException would only occur for a non-numeric string like "abc".

Memory tip: Think of assertions as a "practice mode" switch - they ship off by default so production performance isn't affected, and you flip them on with -ea only when debugging or testing. On the exam, whenever you see assert without -ea in the command, treat that line as if it doesn't exist.

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