Complete the following JPA custom converter class code, such that it serializes a value of type List<GenreEL> to String.:

@Converter
public class GenreConverter implements 
    AttributeConverter<_____________, ___________> {
  @Override
  public String convertToDatabaseColumn( 
      List<GenreEL> attributeValue) { ... }
}

Complete the definition of the languages property such that a minimum of three values are required.

@Entity
public class Book {
  @__________________
  private Set<LanguagesEL> languages;
}           

Which is the appropriate JPA annotation, including parameter(s), such that the value of the genre property is serialized and stored as enumeration literal name, i.e., as String, and not as ordinal values (indexes):

@Entity
public class Book {
  @Enumerated(_________________)
  @NotNull( message="A genre is required!")
  private GenreEL genre;
  ...
}

Which of the following is the name of a JSF element that can be used for rendering a choice widget for a single-valued enumeration attribute?

Complete the following facelet code, such that the resulting HTML code consists of a checkbox group allowing to select multiple languages, when creating a new Book instance::

<h:form id="createBookForm">
  ...
  <h:outputLabel for="languages" value="Select languages " />
    <h:____________________ id="languages" value="#{book.languages}">
      <f:____________________ value="#{book.languageItems}" />
    </h:____________________>
  <h:/outputLabel>
  ...
</h:form>>