@Entity public class AnEntity
{
  // With field based access fields are persistent by default.
  private int someField;
  private String someOtherField;

  // Relationships among entities must be annotated.
  @OneToMany private Collection<AnotherEntity> relatedEntities;

  // Every entity must have a primary key.
  @Id private long aKeyField;

  // Field that is not persistent
  @Transient private String aTransientString;

  // Obligatory constructor with no arguments
  public AnEntity () { ... }

  // Additional business methods ...
  public void myMethodOne (int iArgument) { ... }
  public int myMethodTwo (Object oArgument) { ... }
}