In JPA, any class or POJO (Plain Old Java Object) can be converted to an entity with very few modifications. The following listing shows an entity Customer.java with attributes id, which is unique for a Customer instance, and firstName and lastName.
package ejb30.entity;
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class Customer implements java.io.Serializable {
private int id;
private String firstName;
private String lastName;
public Customer() {}
@Id
public int getId() { return id; }
public void setId(int id) { this.id = id; }
public String getFirstname() { return firstName; }
public void setFirstname(String firstName) {
this.firstName = firstName;
}
public String getLastname() { return lastName; }
public void setLastname(String lastName) {
this.lastName = lastName;
}
public String toString() {
return "[Customer Id =" + id + ",first name=" +
firstName + ",last name=" + lastName + "]";
}
}
The class follows the usual JavaBean rules. The instance...