The Java Persistence API (JPA) was introduced to Java EE in version 5 of the specification. Like its name implies, it is used to persist data to a relational database management system. JPA is a replacement for the Entity Beans that were used in J2EE. Java EE Entities are regular Java classes; the Java EE container knows these classes are Entities because they are decorated with the @Entity annotation. Let's look at an Entity mapping to the CUSTOMER table in the CUSTOMERDB database:
package net.ensode.javaee8book.jpaintro.entity; import java.io.Serializable; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.Table; @Entity @Table(name = "CUSTOMERS") ...