[Java][JPA] xml vs. annotation models mapping

Company.java

package com.gem.demo.database.model;

public class Company {
    public int id;
    public String name;
    public String address;

    ...

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

Employee.java

package com.gem.demo.database.model;

import javax.persistence.*;

@Entity
public class Employee {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    public int id;
    public String firstName;
    public String lastName;
    public double salary;

    ...

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

models-mapping.xml

<?xml version="1.0" encoding="UTF-8"?>
<entity-mappings
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns="http://java.sun.com/xml/ns/persistence/orm"
        xsi:schemaLocation="http://java.sun.com/xml/ns/persistence/orm orm_2_0.xsd"
        version="2.0">
    <description>The minimal mappings for a persistent entity in XML.</description>
    <package>com.gem.demo.database.model</package>

    <entity name="Company" class="com.gem.demo.database.model.Company" access="FIELD">
        <table name="COMPANY"/>
        <attributes>
            <id name="id">
                <generated-value strategy="IDENTITY"/>
            </id>
            <basic name="name">
                <column name="COMPANY_NAME" length="100"/>
            </basic>
            <basic name="address">
            </basic>
        </attributes>
    </entity>
</entity-mappings>

persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns="http://java.sun.com/xml/ns/persistence"
        xsi:schemaLocation="http://java.sun.com/xml/ns/persistence persistence_2_0.xsd"
        version="2.0">

    <persistence-unit name="acme" transaction-type="RESOURCE_LOCAL">
        <description>Persistence Unit</description>
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>

        <class>com.gem.demo.database.model.Employee</class>
        <!-- If mappig file is "orm.xml", no need to inject it into "persistence.xml" -->
        <mapping-file>META-INF/models-mapping.xml</mapping-file>

        <properties>
            <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/sample-jpa"/>
            <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
            <property name="javax.persistence.jdbc.user" value="root"/>
            <property name="javax.persistence.jdbc.password" value="qwerty"/>

            <!-- EclipseLink Configuration -->
            <property name="eclipselink.ddl-generation" value="create-tables"/>
            <property name="eclipselink.logging.level.sql" value="FINE"/>
        </properties>
    </persistence-unit>
</persistence>