[Java][JPA] Field vs. Property Access

EclipseLink.out

...
[EL Fine]: sql: 2015-08-30 10:11:24.497--ServerSession(1622006612)--Connection(530410619)--SELECT ID, NAME, SALARY FROM EMPLOYEE WHERE (ID = ?)
	bind => [1 parameter bound]
Employee.setName(KiT)     // when manager.find(Employee.class, id);
Employee.getName() => KiT
Employee.setName(KiT)
Employee.getName() => KiT
Employee.setName(KiT)
Employee #1: KiT (12345)
Employee.getName() => KiT // when transaction.commit();
Employee.getName() => KiT
...

Employee.java

import javax.persistence.*;

@Entity
@Access(AccessType.FIELD)   // necessary for mixed fields and properties access (except Hibernate)
public class Employee {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;
    private String name;    // Hibernate can define @Access(PROPERTY) here
    private long salary;

    @Basic
    @Access(AccessType.PROPERTY)
    public String getName() {
        System.out.printf("Employee.getName() => %s%n", name);
        return name;
    }

    public void setName(String name) {
        System.out.printf("Employee.setName(%s)%n", name);
        this.name = name;
    }

    @Override
    public String toString() {
        return String.format("Employee #%d: %s (%d)", id, name, salary);
    }
}

Hibernate.out

...
Hibernate: 
    select
        employee0_.id as id1_0_0_,
        employee0_.name as name2_0_0_,
        employee0_.salary as salary3_0_0_ 
    from
        Employee employee0_ 
    where
        employee0_.id=?
Employee.setName(KiT)
Employee #1: KiT (12345)
...

OpenJPA.out

...
1693  pu  TRACE  [main] openjpa.jdbc.SQL - <t 1270038388, conn 1973233403> executing prepstmnt 1806431167 SELECT t0.name, t0.salary FROM Employee t0 WHERE t0.id = ? [params=?]
1694  pu  TRACE  [main] openjpa.jdbc.SQL - <t 1270038388, conn 1973233403> [1 ms] spent
Employee.setName(null)      // when manager.find(Employee.class, id);
Employee.setName(KiT)
Employee.getName() => KiT
Employee #1: KiT (12345)
...

ServiceJPA.java

import javax.persistence.*;

public class ServiceJPA {
    public static void main(String[] args) {
        EntityManagerFactory factory = Persistence.createEntityManagerFactory("pu");
        EntityManager manager = factory.createEntityManager();
        EntityTransaction transaction = manager.getTransaction();
        transaction.begin();

        Employee employee = manager.find(Employee.class, 1);
        System.out.println(employee);

        transaction.commit();
        manager.close();
        factory.close();
    }
}

External references:

• stackoverflow
• eclipseLink weaving