This chapter provides information to help you work with all of the classes in the Essential Tools Module.
• The first two sections, “Class Groups” and “Abstract and Concrete Classes”, provide different ways to think about the classes: grouped by related function, such as classes related to dates and times, and described in computer science terms, such as abstract and concrete classes.
• The next section, “Common Functionality Among Classes”, describes information that is common to all of the classes, such as persistence, I/O member functions, and memory allocation.