code: @Nullable
    public static Date getDate (@Nullable final XMLGregorianCalendar aCal)
    {
      final GregorianCalendar aGregorianCalendar = getGregorianCalendar (aCal);
      return aGregorianCalendar == null ? null : aGregorianCalendar.getTime ();
    }
docs: Get the passed {@link XMLGregorianCalendar} as {@link Date}.
  
  @param aCal
  The source {@link XMLGregorianCalendar}. May be <code>null</code>.
  @return <code>null</code> if the parameter is <code>null</code>.