Define a Book entity with an indexed field genre

Book.java

@Entity
public class Book extends ManagedEntity implements IManagedEntity
{
  @Identifier(generator = IdentifierGenerator.SEQUENCE)
  @Attribute
  protected long bookId;

  @Attribute
  protected String title;

  @Index
  @Attribute
  protected String genre;

  @Attribute
  protected String description;

  // Getters and setters
}