An Entity Bean is an abstraction representing a state-laden class whose instances are stored in a persistence mechanism such as a relational database. Generally speaking, if a class’s state (that is, its attributes) is more important than its behavior (that is, its methods), then the class is amenable to being implemented as an Entity Bean. BookEaz’s system contained several Entity Beans, including
LineItem. These abstractions from BookEaz’s business domain all pass the “state is more important than behavior” litmus test.
Every instance of an Entity Bean has a unique identity that ...