One of the main goals of JPA was th

One of the main goals of JPA was that it should be simple to use and easy to understand. Although its
problem domain cannot be trivialized or watered down, the technology that enables one to deal with it
can be straightforward and intuitive. In this chapter, we will show how effortless it can be to develop
and use entities.
We will start by describing the basic characteristics of entities. We’ll define what an entity is and
how to create, read, update, and delete it. We’ll also introduce entity managers and how they are
obtained and used. Then we’ll take a quick look at queries and how to specify and execute a query
using the EntityManagerand Queryobjects. The chapter will conclude by showing a simple working
application that runs in a standard Java SE environment and that demonstrates all of the example code
in action.