What is the advantage of abstract class and method???

hi,
* Why a class is declared as abstract???
* What is the use of declaring a class as abstract???
* At what situation abstract class will be used???Thanks
JavaImran

To save you from the wrath of the Java experts on this forum, allow me as a relatively new Java user to advise you: do NOT post homework problems here; you're just going to get told to go google the answer. Which would be a good move on your part. Especially since I found the answer to your questions by googling them myself.

Similar Messages

What is the difference between Abstract class and Interface ?

Hi,
Could u plz tell me the difference between Abstract class and Interface?
Thanks in advance.
Gopi

Lots.
An abstract class can contain some method implementations, or indeed all the method implementations. It may contain methods with all the various access modifiers. It cannot be instantiated. A class may inherit from only a single abstract class.
An interface contains only public method stubs and constants. A class may implement multiple interfaces. An interface cannot (obviously) be instantiated.
Abstract classes are particularly useful when you need to provide a semi-complete implementation for reuse. Interfaces are used more like types.
Look at java.util.* for some good examples of the use of both.

What's the difference between Abstract Class and Interface?

Dear all,
Can anyone give me some hints about this topic?
Thanks.
Leo

an abstract class may have some methods already implemented in the abstract class but an interface has no methods implemented
I think it's just that simple.
For your design needs, you just choose what you need : )
Cheers
Stephen

What is the difference between document class and normal class

Hi,
Please let me know what is the difference between document class and normal class.
And I have no idea which class should call as document class or call as an object.
Thanks
-Actionscript Developer

the document class is invoked immediately when your swf opens. the document class must subclass the sprite or movieclip class.
all other classes are invoked explicitly with code and need not subclass any other class.

What are the advantages of using CACHE and NOCACHE Hint

What are the advantages of using CACHE and NOCACHE Hint & difference of them.I saw one of oracle.sql script have CACHE & oracle rac script include NOCACHE .Why is that

924250 wrote:
In a SOA product include db scripts,when we install the product we want to execute the db script to create sequence both oracle RAC & Oracle db
Oracle DB
CREATE SEQUENCE REG_LOG_SEQUENCE START WITH 1 INCREMENT BY 1 NOCACHE
Oracle RAC DB
CREATE SEQUENCE REG_LOG_SEQUENCE START WITH 1 INCREMENT BY 1 CACHE 20 ORDERas sb mentioned, this has nothing to do with oracle hints.
you'll want to search the documentation about sequences.

What is the diff bet condition class and condition type.

Hello Gurus
What is the diff bet condition class and condition type.
I have seen so many threads on this but not getting the exact usefullness.
Difference between Condition class and Condition Category
What is the difference between condition class and condition category?
Condition class and condition category etc.
As per the knowledge i gained condition class tells the type of the condition ie either price , discount ,taxes etc.
Then please tell me why we require cond category.Please give a business scenario where we can justify it use.

Hi shiva
Difference between Condition Category and Condition Class
Condition Category -
It is the Classification of conditions as per the categories ,Say for example Freight condition types you have the same conditon category
Condition class -
It classifies the condition types as price , discounts , taxes , discount etc
Regards
Srinath

ABSTRACT class and method

Dear all Abaper experts,
I am doubt on a abap object program shown as below. It is a ABSTRACT class and method. However, during compiling, an error message is displayed "The abstract method 'WRITE_STATUS' may not be implemented". What does it mean?
REPORT ZOOP_ABSTRACT.
* Class Declaration
CLASS vehicle DEFINITION ABSTRACT.
PUBLIC SECTION.
    METHODS: accelerate,
             write_status ABSTRACT.
PROTECTED SECTION.
    DATA speed TYPE i.
ENDCLASS.
CLASS plane DEFINITION INHERITING FROM vehicle.
PUBLIC SECTION.
    METHODS: rise.
PROTECTED SECTION.
    DATA altitude TYPE i.
ENDCLASS.
CLASS ship DEFINITION INHERITING FROM vehicle.
ENDCLASS.
* Class Implementation
CLASS vehicle IMPLEMENTATION.
METHOD accelerate.
    speed = speed + 1.
ENDMETHOD.
ENDCLASS.
CLASS plane IMPLEMENTATION.
METHOD rise.
    altitude = altitude + 1.
ENDMETHOD.
METHOD write_status.
    WRITE: / 'Plane speed:', speed.
    WRITE: / 'Altitude:', altitude.
ENDMETHOD.
ENDCLASS.
CLASS ship IMPLEMENTATION.
ENDCLASS.
* Global Data
DATA: plane_ref TYPE REF TO plane,
      ship_ref TYPE REF TO ship.
* Classical Processing Blocks
START-OF-SELECTION.
CREATE OBJECT: plane_ref,
                 ship_ref.
CALL METHOD: plane_ref->accelerate,
               plane_ref->rise,
               plane_ref->write_status,
               plane_ref->accelerate,
               plane_ref->write_status.
All answers are welcome and appreciate for the help.

Hi,
try this code I've rearranged your Class Implementation and just added the foll code;
write_status REDEFINITION in the Definition part of the Subclass.
* Class Declaration
CLASS vehicle DEFINITION ABSTRACT.
PUBLIC SECTION.
    METHODS: accelerate,
             write_status ABSTRACT.
PROTECTED SECTION.
    DATA speed TYPE i.
ENDCLASS.
* Class Implementation
CLASS vehicle IMPLEMENTATION.
METHOD accelerate.
    speed = speed + 1.
ENDMETHOD.
ENDCLASS.
CLASS plane DEFINITION INHERITING FROM vehicle.
PUBLIC SECTION.
    METHODS: rise,
             write_status redefinition.
PROTECTED SECTION.
    DATA altitude TYPE i.
ENDCLASS.
CLASS plane IMPLEMENTATION.
METHOD rise.
    altitude = altitude + 1.
ENDMETHOD.
METHOD write_status.
    WRITE: / 'Plane speed:', speed.
    WRITE: / 'Altitude:', altitude.
ENDMETHOD.
ENDCLASS.
CLASS ship DEFINITION INHERITING FROM vehicle.
PUBLIC SECTION.
    METHODS: write_status redefinition.
ENDCLASS.
CLASS ship IMPLEMENTATION.
METHOD write_status.
    WRITE: / 'In Ship Class.'.
ENDMETHOD.
ENDCLASS.
* Global Data
DATA: plane_ref TYPE REF TO plane,
      ship_ref TYPE REF TO ship.
* Classical Processing Blocks
START-OF-SELECTION.
CREATE OBJECT: plane_ref,
                 ship_ref.
CALL METHOD: plane_ref->accelerate,
               plane_ref->rise,
               plane_ref->write_status,
               plane_ref->accelerate,
               plane_ref->write_status,
               ship_ref->write_status.
Best Regards,
Sunil.

Java abstract classes and methods

Can anyone please tell me any real time example of abstract classes and methods.
I want to know its real use. If anyone have ever used it for some purpose while programming please do tell me.

Ashu_Web wrote:
No please.. I just want to know if you have used it while programming. Like "an abstract class can be used to put all the common method names in it without having to write actual implementation code."That would describe an Interface better than an abstract class. Abstract classes usually have at least some implementation.
I want to know its usage in programming, not just a definition. I guess you understand what I am looking for.Yes, and I gave you one: java.util.AbstractList. It can be found inside the src.zip in your JDK directory and it is a pretty good example for an abstract class that provides some implementation and defines exactly what is necessary to make a full List implementation.

What is the advantage to connecting iPad and mini thru Bluetooth

What is the advantage to pairing my iPad with my Mac Mini?

None, as you won't be able to achieve much by doing so. Bluetooth on the iPad is mainly for headphones and keyboards - supported profiles : http://support.apple.com/kb/HT3647

What is the fundamental difference between classful and classless routing?

Hello to all,
After reading several RFCs, guides and HOWTOs I am confused by an apparently trivial question - what is the basic, fundamental difference between classful and classless routing?
I am well aware that - said in a very primitive way - the classful routing does not make use of netmasks and instead uses the address classes while the classless routing utilizes the netmasks and does not evaluate the address classes.
However, already in 1985 the RFC 950 (Internet Standard Subnetting Procedure) stated that the networks can be further subnetted using the network mask. Since then the routers are expected to use network masks in the routing decision process in the precise way they use it nowadays. However, if the routers use network masks they are doing the classless routing, aren't they? Where is then the difference if we used to describe the 80's way of routing as a classful routing? Or was it already the classless routing? The RFCs about CIDR came gradually only in 1992 and 1993.
If somebody could give me an insight into the key difference between classful and classless routing (and perhaps into the Internet history, how was the real routing done then) I would be most grateful.
Thank you a lot!
Regards,
Peter

Hello Mohammed,
I am afraid we still have not understood each other ;) I am not looking for the algorithms used to select the best path. I am well aware of them, both Ford-Bellman and Dijkstra, and about their internals. By the way, these algorithms do not have any influence whether the routing is classful or classless because they deal with metrics, not with masks. For example, a classless EIGRP internally uses a distance-vector algorithm, not a SPF algorithm.
I will try to explain once more what is my problem... There are two terms commonly used but badly defined: the classless routing and classful routing. Originally, I have thought that the classful routing works as follows:
- The routing table consists only of classful destination networks (major nets), metrics and respective gateways. No network masks are stored in the table because we are classful, that is, we use exclusively the route classes and all entries in the routing table are already classful.
- When routing a packet, the router looks at its destination IP address and determines the major net of this IP address (that is, the classful network that this IP address belongs to). Then it looks up the corresponding entry in the routing table and sends the packet to the respective gateway.
I thought that the classful routing works in this way. I won't describe the classless routing - both of us know how do the today's routers select the next hop.
However, in the RFCs 917 and 950 which were published in 1985, long ago before the term 'classless routing' was coined, the network mask was already defined and it was stated how the routers should work with it.
Now I am confused. The terms classless addresses and classless routing were defined sometime in 1990's, therefore I assume that the routing before the invention of classless IP assignment can be in fact described as classful. In other words, I thought that the routing that was commonly used in 1980's did not use netmasks and can be described as classful because the notion of classlessness came first in 1990's. But now I see that netmasks were defined in 1985.
Now where am I wrong? Do I understand the classful routing properly as I described it? Is it correct to talk about routing in that era as classful although the netmasks were already in use? Or was it already the classless routing?
Basically I am trying to understand what was called the classful routing if the classless routing is said to be something different.
Mohammed, I am most grateful to you for your patience and suggestions! Thank you indeed.
Regards,
Peter

What is the difference between div class and div id

I have managed to achieve a two colum css within my content. I normally use "div id" but when I did my two colums it only worked (for me anyway) if the content was a "class" and the right content a "div". Why is this? Is this incorrect?
This is my code
.content {
          height: 400px;
          width: 300px;
          background-color: #FF0;
          float: left;
#rightcontent {
          width: 694px;
          background-color: #0FF;
          float: right;
          height: 400px;
If I try to have content as "id" it disapears.
Thank you in anticipation. Karen

If I change the div class to id, then my box on the left hand side disappears. This is the code below. I set the page up like that as it's more of a banner so I can have my promotions at the top of my page, so no I guess I should not have used "content".. Then I was going to have a content area and then a footer for my links to pages.
<div class ="content">
<p>Our Fantastic New Design</p>
</div>
<div id="rightcontent"></div>
</div>
</body>
</html>
New question - I want to copy my header and dropdown menu on all of my other pages, I was practicing last night but it did not work.
I linked the dropdown menu css to a new page, but I did not link the css styles as I dont want all of my pages being the same. Originally I just copied one page to another, that's when I found out that if I changed one page then it changed the other, does that mean I need to set up all new css styles for each page?
below is what I copied to create the header and dropdown menu on each page.
<div class="container">
<div class="header"></div>
<div id="wrapper">
<div id="navMenu">
<ul>
<li><a href="#">Home</a>
<ul>
<li><a href="#">link item</a></li>
<li><a href="#">link item</a></li>
<li><a href="#">link item</a></li>
<li><a href="#">link item</a></li>
<li><a href="#">link item</a></li>
    </ul> <!end inner ul-->
</li> <!end li-->
</ul> <!end main ul-->
<br class="clearFloat" />
</div> <!end navMenu->
</div> <!end wrapper->
I obviously copied all of my links!
www.bristolequestrianservices.co.uk

Could you please send me the material Opps concepts Classes and Methods

Hi Experts,
I am working on Opps concepts.I am new to this concept.
Could you please send me the detailed presentation on Abap oops.
Thanks inadvance,
Regards,
Rekha.

Hi this will help u.
OOPs ABAP uses Classes and Interfaces which uses Methods and events.
If you have Java skills it is advantage for you.
There are Local classes as well as Global Classes.
Local classes we can work in SE38 straight away.
But mostly it is better to use the Global classes.
Global Classes or Interfaces are to be created in SE24.
SAP already given some predefined classes and Interfaces.
This OOPS concepts very useful for writing BADI's also.
So first create a class in SE 24.
Define attributes, Methods for that class.
Define parameters for that Method.
You can define event handlers also to handle the messages.
After creation in each method write the code.
Methods are similar to ABAP PERFORM -FORM statements.
After the creation of CLass and methods come to SE38 and create the program.
In the program create a object type ref to that class and with the help of that Object call the methods of that Class and display the data.
Example:
REPORT sapmz_hf_alv_grid .
Type pool for icons - used in the toolbar
TYPE-POOLS: icon.
TABLES: zsflight.
To allow the declaration of o_event_receiver before the
lcl_event_receiver class is defined, decale it as deferred in the
start of the program
CLASS lcl_event_receiver DEFINITION DEFERRED.
G L O B A L I N T E R N A L T A B L E S
*DATA: gi_sflight TYPE STANDARD TABLE OF sflight.
To include a traffic light and/or color a line the structure of the
table must include fields for the traffic light and/or the color
TYPES: BEGIN OF st_sflight.
INCLUDE STRUCTURE zsflight.
Field for traffic light
TYPES: traffic_light TYPE c.
Field for line color
types: line_color(4) type c.
TYPES: END OF st_sflight.
TYPES: tt_sflight TYPE STANDARD TABLE OF st_sflight.
DATA: gi_sflight TYPE tt_sflight.
G L O B A L D A T A
DATA: ok_code LIKE sy-ucomm,
Work area for internal table
g_wa_sflight TYPE st_sflight,
ALV control: Layout structure
gs_layout TYPE lvc_s_layo.
Declare reference variables to the ALV grid and the container
DATA:
go_grid TYPE REF TO cl_gui_alv_grid,
go_custom_container TYPE REF TO cl_gui_custom_container,
o_event_receiver TYPE REF TO lcl_event_receiver.
DATA:
Work area for screen 200
g_screen200 LIKE zsflight.
Data for storing information about selected rows in the grid
DATA:
Internal table
gi_index_rows TYPE lvc_t_row,
Information about 1 row
g_selected_row LIKE lvc_s_row.
C L A S S E S
CLASS lcl_event_receiver DEFINITION.
PUBLIC SECTION.
METHODS:
handle_toolbar FOR EVENT toolbar OF cl_gui_alv_grid
IMPORTING
e_object e_interactive,
handle_user_command FOR EVENT user_command OF cl_gui_alv_grid
IMPORTING e_ucomm.
ENDCLASS.
CLASS lcl_event_receiver IMPLEMENTATION
CLASS lcl_event_receiver IMPLEMENTATION.
METHOD handle_toolbar.
Event handler method for event toolbar.
CONSTANTS:
Constants for button type
c_button_normal TYPE i VALUE 0,
c_menu_and_default_button TYPE i VALUE 1,
c_menu TYPE i VALUE 2,
c_separator TYPE i VALUE 3,
c_radio_button TYPE i VALUE 4,
c_checkbox TYPE i VALUE 5,
c_menu_entry TYPE i VALUE 6.
DATA:
ls_toolbar TYPE stb_button.
Append seperator to the normal toolbar
CLEAR ls_toolbar.
MOVE c_separator TO ls_toolbar-butn_type..
APPEND ls_toolbar TO e_object->mt_toolbar.
Append a new button that to the toolbar. Use E_OBJECT of
event toolbar. E_OBJECT is of type CL_ALV_EVENT_TOOLBAR_SET.
This class has one attribute MT_TOOLBAR which is of table type
TTB_BUTTON. The structure is STB_BUTTON
CLEAR ls_toolbar.
MOVE 'CHANGE' TO ls_toolbar-function.
MOVE icon_change TO ls_toolbar-icon.
MOVE 'Change flight' TO ls_toolbar-quickinfo.
MOVE 'Change' TO ls_toolbar-text.
MOVE ' ' TO ls_toolbar-disabled.
APPEND ls_toolbar TO e_object->mt_toolbar.
ENDMETHOD.
METHOD handle_user_command.
Handle own functions defined in the toolbar
CASE e_ucomm.
WHEN 'CHANGE'.
PERFORM change_flight.
LEAVE TO SCREEN 0.
ENDCASE.
ENDMETHOD.
ENDCLASS.
S T A R T - O F - S E L E C T I O N.
START-OF-SELECTION.
SET SCREEN '100'.
*& Module USER_COMMAND_0100 INPUT
MODULE user_command_0100 INPUT.
CASE ok_code.
WHEN 'EXIT'.
LEAVE TO SCREEN 0.
ENDCASE.
ENDMODULE. " USER_COMMAND_0100 INPUT
*& Module STATUS_0100 OUTPUT
MODULE status_0100 OUTPUT.
DATA:
For parameter IS_VARIANT that is sued to set up options for storing
the grid layout as a variant in method set_table_for_first_display
l_layout TYPE disvariant,
Utillity field
l_lines TYPE i.
After returning from screen 200 the line that was selected before
going to screen 200, should be selected again. The table gi_index_rows
was the output table from the GET_SELECTED_ROWS method in form
CHANGE_FLIGHT
DESCRIBE TABLE gi_index_rows LINES l_lines.
IF l_lines > 0.
CALL METHOD go_grid->set_selected_rows
EXPORTING
it_index_rows = gi_index_rows.
CALL METHOD cl_gui_cfw=>flush.
REFRESH gi_index_rows.
ENDIF.
Read data and create objects
IF go_custom_container IS INITIAL.
Read data from datbase table
PERFORM get_data.
Create objects for container and ALV grid
CREATE OBJECT go_custom_container
EXPORTING container_name = 'ALV_CONTAINER'.
CREATE OBJECT go_grid
EXPORTING
i_parent = go_custom_container.
Create object for event_receiver class
and set handlers
CREATE OBJECT o_event_receiver.
SET HANDLER o_event_receiver->handle_user_command FOR go_grid.
SET HANDLER o_event_receiver->handle_toolbar FOR go_grid.
Layout (Variant) for ALV grid
l_layout-report = sy-repid. "Layout fo report
Setup the grid layout using a variable of structure lvc_s_layo
Set grid title
gs_layout-grid_title = 'Flights'.
Selection mode - Single row without buttons
(This is the default mode
gs_layout-sel_mode = 'B'.
Name of the exception field (Traffic light field) and the color
field + set the exception and color field of the table
gs_layout-excp_fname = 'TRAFFIC_LIGHT'.
gs_layout-info_fname = 'LINE_COLOR'.
LOOP AT gi_sflight INTO g_wa_sflight.
IF g_wa_sflight-paymentsum < 100000.
Value of traffic light field
g_wa_sflight-traffic_light = '1'.
Value of color field:
C = Color, 6=Color 1=Intesified on, 0: Inverse display off
g_wa_sflight-line_color = 'C610'.
ELSEIF g_wa_sflight-paymentsum => 100000 AND
g_wa_sflight-paymentsum < 1000000.
g_wa_sflight-traffic_light = '2'.
ELSE.
g_wa_sflight-traffic_light = '3'.
ENDIF.
MODIFY gi_sflight FROM g_wa_sflight.
ENDLOOP.
Grid setup for first display
CALL METHOD go_grid->set_table_for_first_display
EXPORTING i_structure_name = 'SFLIGHT'
is_variant = l_layout
i_save = 'A'
is_layout = gs_layout
CHANGING it_outtab = gi_sflight.
*-- End of grid setup -
Raise event toolbar to show the modified toolbar
CALL METHOD go_grid->set_toolbar_interactive.
Set focus to the grid. This is not necessary in this
example as there is only one control on the screen
CALL METHOD cl_gui_control=>set_focus EXPORTING control = go_grid.
ENDIF.
ENDMODULE. " STATUS_0100 OUTPUT
*& Module USER_COMMAND_0200 INPUT
MODULE user_command_0200 INPUT.
CASE ok_code.
WHEN 'EXIT200'.
LEAVE TO SCREEN 100.
WHEN'SAVE'.
PERFORM save_changes.
ENDCASE.
ENDMODULE. " USER_COMMAND_0200 INPUT
*& Form get_data
FORM get_data.
Read data from table SFLIGHT
SELECT *
FROM zsflight
INTO TABLE gi_sflight.
ENDFORM. " load_data_into_grid
*& Form change_flight
Reads the contents of the selected row in the grid, ans transfers
the data to screen 200, where it can be changed and saved.
FORM change_flight.
DATA:l_lines TYPE i.
REFRESH gi_index_rows.
CLEAR g_selected_row.
Read index of selected rows
CALL METHOD go_grid->get_selected_rows
IMPORTING
et_index_rows = gi_index_rows.
Check if any row are selected at all. If not
table gi_index_rows will be empty
DESCRIBE TABLE gi_index_rows LINES l_lines.
IF l_lines = 0.
CALL FUNCTION 'POPUP_TO_DISPLAY_TEXT'
EXPORTING
textline1 = 'You must choose a line'.
EXIT.
ENDIF.
Read indexes of selected rows. In this example only one
row can be selected as we are using gs_layout-sel_mode = 'B',
so it is only ncessary to read the first entry in
table gi_index_rows
LOOP AT gi_index_rows INTO g_selected_row.
IF sy-tabix = 1.
READ TABLE gi_sflight INDEX g_selected_row-index INTO g_wa_sflight.
ENDIF.
ENDLOOP.
Transfer data from the selected row to screenm 200 and show
screen 200
CLEAR g_screen200.
MOVE-CORRESPONDING g_wa_sflight TO g_screen200.
LEAVE TO SCREEN '200'.
ENDFORM. " change_flight
*& Form save_changes
Changes made in screen 200 are written to the datbase table
zsflight, and to the grid table gi_sflight, and the grid is
updated with method refresh_table_display to display the changes
FORM save_changes.
DATA: l_traffic_light TYPE c.
Update traffic light field
Update database table
MODIFY zsflight FROM g_screen200.
Update grid table , traffic light field and color field.
Note that it is necessary to use structure g_wa_sflight
for the update, as the screen structure does not have a
traffic light field
MOVE-CORRESPONDING g_screen200 TO g_wa_sflight.
IF g_wa_sflight-paymentsum < 100000.
g_wa_sflight-traffic_light = '1'.
C = Color, 6=Color 1=Intesified on, 0: Inverse display off
g_wa_sflight-line_color = 'C610'.
ELSEIF g_wa_sflight-paymentsum => 100000 AND
g_wa_sflight-paymentsum < 1000000.
g_wa_sflight-traffic_light = '2'.
clear g_wa_sflight-line_color.
ELSE.
g_wa_sflight-traffic_light = '3'.
clear g_wa_sflight-line_color.
ENDIF.
MODIFY gi_sflight INDEX g_selected_row-index FROM g_wa_sflight.
Refresh grid
CALL METHOD go_grid->refresh_table_display.
CALL METHOD cl_gui_cfw=>flush.
LEAVE TO SCREEN '100'.
ENDFORM. " save_changes
chk this blog
/people/vijaybabu.dudla/blog/2006/07/21/topofpage-in-alv-using-clguialvgrid
with regards,
Hema.
pls give points if helpful.

What is the benefit of abstract classes?

I am little bit confuse regarding the benefits of the abstract classes. Can anybody helps me in this regard. I just want to know when and what situation we may decide that particular class needs an abstract method.
Thanx

I am little bit confuse regarding the benefits of the
abstract classes. Can anybody helps me in this
regard. I just want to know when and what situation
we may decide that particular class needs an abstract
method.Sorry if I sound weary of this question, but it is asked about 3-4 times a week. Rather than have us go through this tired exercise again, please search the forum for previous threads on this subject. You'll find about a gazillion. In fact, it's often a good idea to search the forum before asking a question as very often it has been asked and answered before.

What is the relation between main class and inner classes

hi
i want to make a UML design and o want to know how to draw the relation betwwen the main public class and inner classes?
and what is the relation?

BaffyOfDaffyA wrote:
Please keep in mind that if you spell better you will get better answers and if you add duke stars you will get better answers and if you mark the thread as a question you will get better answers. That will make it look like you are paying attention and that you really want an answer.
My best answer based on your rather vague question:
A minimal public class in a file named "Minimal.java" in the directory named "minimal":
package minimal;
public class Minimal {
private int variable;
public Minimal(int var) {
variable = var;
public int getVariable() {
return variable;
}This would be an example of adding an inner class:
package minimal;
public class Minimal {
private int variable;
public Minimal(int var) {
variable = var;
public int getVariable() {
return variable;
public class Inner {
private int innerVariable;
public Inner(int var) {
innerVariable = var;
public int getInnerVariable() {
return innerVariable;
}The inner class is exactly like any other inner class except if you are accessing it from anything else other than Minimal then you would have to add Minimal. right before Inner for example, where the Minimal class could use
Inner inner = new Inner(5);other classes would have to use
Minimal.Inner inner = new Minimal.Inner(5);
See [Inner Class Example|http://java.sun.com/docs/books/tutorial/java/javaOO/innerclasses.html] or [Nested Classes|http://java.sun.com/docs/books/tutorial/java/javaOO/nested.html] for more information.
He is probably not asking what an inner class is or how to declare one in raw source code. To me he is asking how do I
explain this relationship in a UML diagram and as UML is not and exact science and expression can vary a lot
between UML design applications I didn't want to stab in the dark.
@OP I would say whatever seems most logical to you and your team, write something that reads.

Abstract classes and methods with dollar.decimal not displaying correctly

Hi, I'm working on a homework assignment and need a little help. I have two classes, 1 abstract class, 1 extends class and 1 program file. When I run the program file, it executes properly, but the stored values are not displaying correctly. I'm trying to get them to display in the dollar format, but it's leaving off the last 0. Can someone please offer some assistance. Here's what I did.
File 1
public abstract class Customer//Using the abstract class for the customer info
private String name;//customer name
private String acctNo;//customer account number
private int branchNumber;//The bank branch number
//The constructor accepts as arguments the name, acctNo, and branchNumber
public Customer(String n, String acct, int b)
    name = n;
    acctNo = acct;
    branchNumber = b;
//toString method
public String toString()
String str;
    str = "Name: " + name + "\nAccount Number: " + acctNo + "\nBranch Number: " + branchNumber;
    return str;
//Using the abstract method for the getCurrentBalance class
public abstract double getCurrentBalance();
}file 2
public class AccountTrans extends Customer //
    private final double
    MONTHLY_DEPOSITS = 100,
    COMPANY_MATCH = 10,
    MONTHLY_INTEREST = 1;
    private double monthlyDeposit,
    coMatch,
    monthlyInt;
    //The constructor accepts as arguments the name, acctNo, and branchNumber
    public AccountTrans(String n, String acct, int b)
        super(n, acct, b);
    //The setMonthlyDeposit accepts the value for the monthly deposit amount
    public void setMonthlyDeposit(double deposit)
        monthlyDeposit = deposit;
    //The setCompanyMatch accepts the value for the monthly company match amount
    public void setCompanyMatch(double match)
        coMatch = match;
    //The setMonthlyInterest accepts the value for the monthly interest amount
    public void setMonthlyInterest(double interest)
        monthlyInt = interest;
    //toString method
    public String toString()
        String str;
        str = super.toString() +
        "\nAccount Type: Hybrid Retirement" +
        "\nDeposits: $" + monthlyDeposit +
        "\nCompany Match: $" + coMatch +
        "\nInterest: $" + monthlyInt;
        return str;
    //Using the getter method for the customer.java fields
    public double getCurrentBalance()
        double currentBalance;
        currentBalance = (monthlyDeposit + coMatch + monthlyInt) * (2);
        return currentBalance;
}File 3
    public static void main(String[] args)
//Creates the AccountTrans object
        AccountTrans acctTrans = new AccountTrans("Jane Smith", "A123ZW", 435);
        //Created to store the values for the MonthlyDeposit,
        //CompanyMatch, MonthlyInterest
        acctTrans.setMonthlyDeposit(100);
        acctTrans.setCompanyMatch(10);
        acctTrans.setMonthlyInterest(5);
        DecimalFormat dollar = new DecimalFormat("#,##0.00");
        //This will display the customer's data
        System.out.println(acctTrans);
        //This will display the current balance times 2 since the current
        //month is February.
        System.out.println("Your current balance is $"
                + dollar.format(acctTrans.getCurrentBalance()));
    }

Get a hair cut!
h1. The Ubiquitous Newbie Tips
* DON'T SHOUT!!!
* Homework dumps will be flamed mercilessly. [Feelin' lucky, punk? Well, do ya'?|http://www.youtube.com/watch?v=1-0BVT4cqGY]
* Have a quick scan through the [Forum FAQ's|http://wikis.sun.com/display/SunForums/Forums.sun.com+FAQ].
h5. Ask a good question
* Don't forget to actually ask a question. No, The subject line doesn't count.
* Don't even talk to me until you've:
    (a) [googled it|http://www.google.com.au/] and
    (b) had a squizzy at the [Java Cheat Sheet|http://mindprod.com/jgloss/jcheat.html] and
    (c) looked it up in [Sun's Java Tutorials|http://java.sun.com/docs/books/tutorial/] and
    (d) read the relevant section of the [API Docs|http://java.sun.com/javase/6/docs/api/index-files/index-1.html] and maybe even
    (e) referred to the JLS for "advanced" questions.
* [Good questions|http://www.catb.org/~esr/faqs/smart-questions.html#intro] get better Answers. It's a fact. Trust me on this one.
    - Lots of regulars on these forums simply don't read badly written questions. It's just too frustrating.
      - FFS spare us the SMS and L33t speak! Pull your pants up, and get a hair cut!
    - Often you discover your own mistake whilst forming a "Good question".
    - Often you discover that you where trying to answer "[the wrong question|http://blog.aisleten.com/2008/11/20/youre-asking-the-wrong-question/]".
    - Many of the regulars on these forums will bend over backwards to help with a "Good question",
      especially to a nuggetty problem, because they're interested in the answer.
* Improve your chances of getting laid tonight by writing an SSCCE
    - For you normal people, That's a: Short Self-Contained Compilable (Correct) Example.
    - Short is sweet: No-one wants to wade through 5000 lines to find your syntax errors!
    - Often you discover your own mistake whilst writing an SSCCE.
    - Often you solve your own problem whilst preparing the SSCCE.
    - Solving your own problem yields a sense of accomplishment, which makes you smarter ;-)
h5. Formatting Matters
* Post your code between a pair of {code} tags
    - That is: {code} ... your code goes here ... {code}
    - This makes your code easier to read by preserving whitespace and highlighting java syntax.
    - Copy&paste your source code directly from your editor. The forum editor basically sucks.
    - The forums tabwidth is 8, as per [the java coding conventions|http://java.sun.com/docs/codeconv/].
      - Indents will go jagged if your tabwidth!=8 and you've mixed tabs and spaces.
      - Indentation is essential to following program code.
      - Long lines (say > 132 chars) should be wrapped.
* Post your error messages between a pair of {code} tags:
    - That is: {code} ... errors here ... {code}
    - OR: [pre]{noformat} ... errors here ... {noformat}[/pre]
    - To make it easier for us to find, Mark the erroneous line(s) in your source-code. For example:
        System.out.println("Your momma!); // <<<< ERROR 1
    - Note that error messages are rendered basically useless if the code has been
      modified AT ALL since the error message was produced.
    - Here's [How to read a stacktrace|http://www.0xcafefeed.com/2004/06/of-thread-dumps-and-stack-traces/].
* The forum editor has a "Preview" pane. Use it.
    - If you're new around here you'll probably find the "Rich Text" view is easier to use.
    - WARNING: Swapping from "Plain Text" view to "Rich Text" scrambles the markup!
    - To see how a posted "special effect" is done, click reply then click the quote button.
If you (the newbie) have covered these bases *you deserve, and can therefore expect, GOOD answers!*
h1. The pledge!
We the New To Java regulars do hereby pledge to refrain from flaming anybody, no matter how gumbyish the question, if the OP has demonstrably tried to cover these bases. The rest are fair game.

What is the advantage of abstract class and method???

Similar Messages

Maybe you are looking for