Java™ How To Program (Early Objects), Tenth Edition

Notes on the Expression in Each case of a switch

When using the switch statement, remember that each case must contain a constant integral expression—that is, any combination of integer constants that evaluates to a constant integer value (e.g., –7, 0 or 221)—or a String. An integer constant is simply an integer value. In addition, you can use character constants—specific characters in single quotes, such as 'A', '7' or '$'—which represent the integer values of characters and enum constants (introduced in Section 6.10). (Appendix B shows the integer values of the characters in the ASCII character set, which is a subset of the Unicode^® character set used by Java.)

The expression in each case can also be a constant variable—a variable containing ...