Analyze the following code.
1 public class Test {
2 public static void main(String[] args) {
3 Number[] numbers = {new Rational(1, 2), new Integer(4), new Double(5.6)};
4 java.util.Arrays.sort(numbers);
5 }
6 }
A. The program has a compile error because numbers is declared as Number[], so you cannot assign {new Rational(1, 2), new Integer(4), new Double(5.6)} to it.B. The program has a runtime error because numbers is declared as Number[], so you cannot assign {new Rational(1, 2), new Integer(4), new Double(5.6)} to it.
C. The program has a compile error because numbers is declared as Number[], so you cannot pass it to Arrays.sort(Object[]).
D. The program has a runtime error because the compareTo methods in Rational, Integer, and Double classes do not compare the value of one type with a value of another type.
The correct answer is D
Explanation: (A) and (B) are incorrect because Rational, Integer, and Double are subclasses of Number and any instances of these classes can be elements of the Number[] array. (C) is incorrect because it is fine to pass an instance of Number[] to a parameter of the Object[] type. (D) is correct because the compareTo method in Rational, Integer, Double only compare two Rational objects, two Integer objects, or two Double objects.
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