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POWhy JPA-2.0 Primary Key Classes have to implement Serializable but my example works without?
 

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  1. POWhy JPA-2.0 Primary Key Classes have to implement Serializable but my example works without?
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    <p>In many sources I have read PrimaryKey Classes and even JPA2 entities should be serializable.</p> <p>IN my example (legacy database) there is a relationship between employee and languages:</p> <p>Employee Class:</p> <pre><code>@Entity @IdClass(EmpleadoId.class) @Table(name = "NO_INFGRAEMPL") public class Empleado { @Id @Column(name = "IGECOMPANIA", unique = true) private String compania; @Id @Column(name = "IGENUMEROIDENTIFIC", unique = true) private String numeroIdentificacion; //... } </code></pre> <p>Employee Compound PrimaryKey Class:</p> <pre><code>public class EmpleadoId { private String compania; private String numeroIdentificacion; //... } </code></pre> <p>Employee Language SKill Class:</p> <pre><code>@Entity @IdClass(IdiomaEmpleadoId.class) @Table(name = "NO_IDIOMEMPLE") public class IdiomaEmpleado { @Id @ManyToOne(fetch = FetchType.LAZY) @JoinColumns(value = { @JoinColumn(name= "IEMCOMPANIA", referencedColumnName = "IGECOMPANIA"), @JoinColumn(name = "IEMEMPLEADO", referencedColumnName = "IGENUMEROIDENTIFIC") }) private Empleado empleado; @Id @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "IEMIDIOMA") private Idioma idioma; @Column(name = "IEMNIVELLECTURA") private String nivelLectura; //... } </code></pre> <p>Employee Language Skill Compound PrimaryKey Class:</p> <pre><code>public class IdiomaEmpleadoId { private EmpleadoId empleado; private String idioma; //... } </code></pre> <p>Language Class:</p> <pre><code>@Entity @Table(name = "NO_IDIOMAS") public class Idioma { @Id @Column(name = "IDICODIGO") private String codigo; @Column(name = "IDIDESCRIPCION") private String descripcion; //... } </code></pre> <p>I am using EclipseLink JPA2 Provider under a J2SE application and it is not giving me any exceptions.</p> <p>My questions are:</p> <ul> <li>Why is it not giving me exceptions? Is it not enforced to have Serializable?</li> <li>Is it safe to continue this way or should I definitely implemente serializable?.</li> <li>In which ones?, JPA2 Entities or PrimaryKey Classes?</li> </ul> <p>Thanks a lot for the help.</p>
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