Question

Which of the following code segments show examples of autoboxing?

Double a = new Double(17.5);
int compareValue = a.compareTo(20.0);

Double d = 15;

String s = "a string";
Integer len = s.length();

Answer 1

Autoboxing in Java is the automatic conversion of primitive types into their corresponding wrapper classes.

Step-by-step explanation:

The student has asked which code segments show examples of autoboxing.

Autoboxing is a feature in Java that automatically converts a primitive type into its corresponding wrapper class whenever an object is required. The code segment Double d = 15; and Integer len = s.length(); are the correct examples of autoboxing. The correct examples of autoboxing provided are 'Double d = 15;' and 'Integer len = s.length();', where integer values are automatically converted to Double and Integer objects, respectively.

The first example, Double a = new Double(17.5);, is not an example of autoboxing, as it uses the constructor to create a Double object. The second example assigns an int value to a Double reference, which triggers autoboxing of the primitive value 15 to a Double object. The third example assigns the result of s.length(), which returns an int, to an Integer reference, which also triggers autoboxing.