What restrictions are placed on the values of each case of a switch statement?

• A. Values must be boolean
• B. Values must evaluate to a value that can be promoted to an int value
• C. Values must be declared as final
• D. Values must be of string type

Answer: (B)

In a switch statement, case values must evaluate to a value that can be promoted to an int value, which encompasses a variety of data types. This includes primitive data types like byte, short, char, and int, as well as their wrapper classes (Byte, Short, Character, Integer). The requirement for case values is based on how the Java switch statement is designed.

When the expression in the switch statement is evaluated, it must result in a type that can be matched against the case values, which are typically constant expressions. The Java language specification allows case values to be integral types and, since Java can implicitly promote smaller integer types to int for these purposes, this makes option B the correct choice.

Other types, such as strings, can also be used as case values in Java, but they are not converted to int, so option D, while occasionally accurate in specific Java versions, does not encompass the broader requirements. The case values do not need to be boolean as indicated by option A, nor must they be declared as final, as stated in option C. While final variables can be used in switch cases, it is not a restriction that all case values must be final.