20.

How the Patterns Are Organized

In this book, to aid in identifying and classifying the following bug patterns, we'll summarize each description using the following form (borrowing some terminology from the medical establishment):

• Pattern name. An easy-to-identify name for the bug.

• Symptoms. Behaviors or results that clue you in to the presence of a bug.

• Causes. The actions, inactions, misdirections, or errors that may be causing the problem.

• Cures and preventions. Methods to fix an existing problem and techniques to keep the problem from raising its annoying head.

Along with each pattern, I'll also discuss broader programming principles and language design issues-such as language expressiveness, static checking, class design, and so on-that may either contribute to or help minimize the occurrence of the pattern. Code samples will be included with each pattern to help the illuminate the problem and ways to correct it.