Sams Teach Yourself Java™ in 24 Hours, Sixth Edition

Creating Class Variables

When you create an object, it has its own version of all variables that are part of the object’s class. Each object created from the Virus class of objects has its own version of the newSeconds, maxFileSize, and author variables. If you modified one of these variables in an object, it would not affect the same variable in another Virus object.

There are times when an attribute should describe an entire class of objects instead of a specific object itself. These are called class variables. If you want to keep track of how many Virus objects are being used in a program, you could use a class variable to store this information. Only one copy of the variable exists for the whole class. The variables you have been creating ...