• RELEVANCY SCORE 5.61

    DB:5.61:Difference B/W Abstract &Amp; Interface dx




    Anyone tell me 4 difference b/w abstract class and interface
    plz help me

    DB:5.61:Difference B/W Abstract &Amp; Interface dx

    Asking once is enough.
    http://forum.java.sun.com/thread.jspa?threadID=734361

  • RELEVANCY SCORE 5.43

    DB:5.43:Difference B/W Abstract Class And Interface mf




    Hi,
    can anyone tell the difference between Abstract class and an Interface?

    Thanks in advance!

    DB:5.43:Difference B/W Abstract Class And Interface mf

    The majoor diiffernce is that Interface canot ber
    inherited while absract calss can be inherited
    one abract class can iheret other abstract class
    while Interface doesnot???

  • RELEVANCY SCORE 5.11

    DB:5.11:Abstract Class And Interface 18




    what is the difference between abstract class and interface

  • RELEVANCY SCORE 5.10

    DB:5.10:Abstract Class And Interface???? ja


    hi all, i would like to know the difference between abstract class and interface....could anybody enlighten me on this....

    DB:5.10:Abstract Class And Interface???? ja

    search the forums, lot's of times answered this one has been.

  • RELEVANCY SCORE 4.72

    DB:4.72:Basic Java Mcq! d7


    I came accros a scjp quesion that is

    Which of the following are legal declerations for non nested classes and interfaces?
    A) final abstract class Test{}
    B) public static interface Test{}
    C) final public class Test{}
    D) protected abstract class Test{}
    E) protected interface Test{}
    F) abstract public class Test{}

    I think B,C,D,E,F are correct.I know that first one is wrong because final and abstract can not be used at the same time.Am i right or wrong?Can any one give me a explanation if i am wrong.

    DB:4.72:Basic Java Mcq! d7

    Also, a good site to see...

    http://www.uni-bonn.de/~manfear/javamodifiers.php

    Regards,
    Sidath.

  • RELEVANCY SCORE 4.32

    DB:4.32:Difference B/W Delivery Class And Data Class In Data Dictionary ad



    please tell me indetail

    difference b/w delivery class and data class in data dictionary

  • RELEVANCY SCORE 4.01

    DB:4.01:Difference Between Interface And Abstract Class zk


    hai

    please tell me what is the difference between interface and abstract class?

    when i want use inteface? when i want use abstrct class?

    give me the simple example for that?......

    DB:4.01:Difference Between Interface And Abstract Class zk

    This thread is moved from "JavaServer Pages (JSP) and JSTL" to here.

  • RELEVANCY SCORE 3.95

    DB:3.95:Abstract Class And Interface 17



    Please tell me what is Abstract Class and Interface. Please explain with help of simple example and also tell me difference between them.

    DB:3.95:Abstract Class And Interface 17


    hi

    i will suggest u to refer some basic java book , to clear ur basic concept of OOPS , because these principal remain same for all languages that follow OOPS concept .

    and under standing these with java is easier then with ABAP .

    Abstract Class

    class which have atleast 1 method which is declared only , (no definition is given for it in this class is mentioned as Abstract Method )

    and that class is defined as Abstract class

    Interface :

    only declaration of method done here , no method will be defined here , class which will implement this interface will give definition .

    Diff. b/w Abstract Class and Interface :

    ABS Class can have method with there definition , but one method should be there with declartion only.

    Interface will have all method with out definition .

    hpoe this help u .

    reward if helpful.

  • RELEVANCY SCORE 3.95

    DB:3.95:What Is The Difference Between An Abstract And An Interface Class? pk


    can anyone enlighten me on this, what is the difference between an interface and an abstract class? When should i use an interface instead of a class and vice-versa? thanks!

    DB:3.95:What Is The Difference Between An Abstract And An Interface Class? pk

    public class Test extends MyClass implements MyInterface {
    public Test() {
    someAbstractMethod();
    someInterface();
    someMethodInAbstractClass();
    super.someMethodInAbstractClass();
    }
    public static void main(String[] args) {
    Test foo = new Test();
    }
    public void someAbstractMethod() {
    System.out.println("someAbstractMethod() in Test");
    }
    public void someInterface() {
    System.out.println("someInterFace() in Test");
    }
    // public void someMethodInAbstractClass() {
    // System.out.println("someMethodInAbstractClass() in Test");
    // }
    }

    abstract class MyClass {
    public void someMethodInAbstractClass() {
    System.out.println("someMethodInAbstractClass() in MyClass");
    }
    public abstract void someAbstractMethod();
    }
    interface MyInterface {
    public void someInterface();
    }Run once, uncomment code, run again, compare output

  • RELEVANCY SCORE 3.90

    DB:3.90:Interface &Amp; Abstract Class d3


    1whats the basic difference between an interface and an abstract class?
    when should one be using an interface or an abstract class?

    2whats the difference between method overriding and method overlaoding?
    does both of them has any relation with the instance of te class implementing them?

    DB:3.90:Interface &Amp; Abstract Class d3

    http://www.google.com/search?q=java+interface+%22abstract+class%22

    http://www.google.com/search?q=java+method+overloading+overriding

  • RELEVANCY SCORE 3.87

    DB:3.87:Interface And Abstract Class ac


    hi all,

    A method in an interface consists of access specifiers as public or abstract. what is the difference if the access specifiers for the method is public and abstract.

    regards,
    priya

    DB:3.87:Interface And Abstract Class ac

    That is correct. They must be because interface methods must be overridden when subclassed.

  • RELEVANCY SCORE 3.86

    DB:3.86:Abstract Class Vs Interface sc


    can anyone pls help me in understanding difference between an interface and an abstract class which has no function with implementation

    which is better abstract cls or interface in term of speed, features..?
    Thanksbahushekh

    DB:3.86:Abstract Class Vs Interface sc

    To Mike Feng or any other moderator,
    Can you unmark
    as answer the previous post from myself please?
    Reason: It has no relevance to the original question, I was just replying to the post preceding it from RudeDog2
    which I also feel, does not really relate to the original question.
    I will leave it to Rudy to decide if He wants that post to be unmarked.

    Regards,

    John

    Click this link to see how to insert a picture into a forum post.

  • RELEVANCY SCORE 3.79

    DB:3.79:Interfaces V/S Abstract Classes???? m3


    Hi Every1
    Can anybody plz tell me the difference b/w "INTERFACE ABSTRACT CLASSES" from design prospective. I have sufficient knowledge on Interfaces and abstract classes in general, but unable to make out when should I use which one? I have read few topics on Java World and from some other sites too, but unable to makeout the difference.
    Topic on "Abstract Classes v/s Interfaces" on Java World says that if your design changes frequently then go for "Interfaces". Why?????
    That tutorial also says "Interfaces are generally used for making Framework. "HOW"????
    I have different thinking...
    Lets say there is one interface called I_Animal and an abstract class called C_Animal, which are as follows:

    interface I_Animal{
    public void move(); // Which tells how different animals move
    }

    Now my Abstract class

    class abstract C_Animal{
    public void move(); // Which tells how different animals move
    }

    Now there 2 classes namely(C1 and C2), C1 implements I_Animal to provide the functionality of move() method.
    C2 extends C_Animal(abstract class) to provide the functionality of move() method.

    class C1 implements I_Animal{
    public void move(){
    // Some functionality
    }
    }

    class C2 extends C_Animal{
    public void move(){
    // Some functionality
    }

    Now what i want to know is which approach is better and "WHY"??
    My thinking is....
    Sometimes using interfaces is advantegeous while sometimes abstract calsses are better, depending upon the requirement and situation

    Lets say in the above example, in future we want to add one more method called eat(). If we r adding eat() method in interface then we have to add the method in the class (which implements that interface) also. So in this case we have to make changes at two different places(namely interface and the implementing class), but if we are adding the move() method in abstract class, we can add it in the abstract class with blank implementation(i.e opening and closing the curly braces like this {}). Here we are not changing the code at two different places. so in this case abstract classes are advantegeous.
    Lets think of a different senario where my class is already extending some other class, then in that case I can't use abstract class because Java doesn't support Multiple Inheritance. So the only way round is to use Interfaces.
    So this is how I differentiate b/w interfaces and abstract classes. Do anyone of you have different thought on this. Plz tell me.

    Any help will be appreciated

    Tx in Advance
    Jam

    DB:3.79:Interfaces V/S Abstract Classes???? m3

    Why are interfaces useful from a design perspective? Because they are less intrusive.

    For instance, take a look at the interface Action and the abstract class AbstractAction in Swing. Say you want to add a button to a toolbar (using JToolBar). The add method accept any object that has type Action. This means that you can add any instances of your own classes with the only requirement that they implement the Action interface. However, if add was designed to take an instance of type AbstractAction, then you would be forced to make your own class inherit from AbstractAction. That is a very intrusive requirement because classes can only inherit from one other class. Requiring that a class implement an interface, on the other hand, is not intrusive because classes can implement more than one interface.

  • RELEVANCY SCORE 3.79

    DB:3.79:Difference Between Inheritance And Abstract Class 9s


    difference between inheritance and abstract class

    DB:3.79:Difference Between Inheritance And Abstract Class 9s

    There was never an episode of Blackadder where he tried to con his aunt out of an abstract class

  • RELEVANCY SCORE 3.78

    DB:3.78:Using Abstract Class fx


    I know how to use abstract class. but I am trying to find a specific case that i have to use ONLY abstract class, but it's kind of hard. here is my example.

    abstract class A
    {
    void move()
    {
    // implementation code necessary for walk() comes here
    walk();
    }

    abstract void walk();
    }

    public class B extends A
    {
    void walk();
    }

    I know that it can't be done by using Interface. but in this case, i can use just regular class for class A by making a method "walk()" a empty method instead of abstract class. Can anybody show me a case that I HAVE TO use only abstract class? I am preparing an interview. And it would be great if someone shows me a case for using only Interface.

    thanks in advance...

    DB:3.78:Using Abstract Class fx

    Using an abstract class, solely from the language standpoint, is a convienence not a necessity.

    Anything that can be done with a abstract class could be done with interfaces and additional classes.

    If you expand from the language to the Java API then there are certainly cases where you must use an abstract class because that is all the API will take.

    And in the same way interfaces are required in the API. Where a specific case would be Serializable.

  • RELEVANCY SCORE 3.78

    DB:3.78:Inherit Abstract Classe fc


    Can anyone show me how to make a class inherit all functionalitied from two difference abstract classes in my progam. thanks

    Jadebui.

    class a extends b ??????????
    {}

    abstract class b
    {}

    abstract class c
    {}

    DB:3.78:Inherit Abstract Classe fc

    if you want to declare both classes(b and c) as abstract you can not do multiple inheritances, try this way

    class a extends b{

    }

    abstract class b extends c{

    }

    abstract class c{

    }or you have to decide to declare one of the abstract classes as an interface

  • RELEVANCY SCORE 3.78

    DB:3.78:Please Differentiate These Codes 17


    I have two classes A(abstract) B ( derived from A)
    Please tell me difference B/w two codes written below using classes A and B

    abstract class A
    {
    public virtual void test()
    {
    Console.WriteLine(A);
    }
    }
    class B:A
    {
    public void test()
    {
    Console.WriteLine(Rect);
    }
    }

    DB:3.78:Please Differentiate These Codes 17

    Hi urprob,

    How is it going now with our friends' suggestions?
    We are looking forward to hearing from you.

    Have a nice day,Leo Liu [MSFT]
    MSDN Community Support | Feedback to us

  • RELEVANCY SCORE 3.76

    DB:3.76:Portal Implementation 39



    Hi

    1) what is the Abstract Portal Component?

    2) what is the IPortalComponenet?

    and what is the difference b/w these two

    3) what is the difference b/w Dynpage and JSPDynpage

    Regards

    sureshbabu

    DB:3.76:Portal Implementation 39


    Hi Suresh,

    These all are various ways in which we can build Portal Applications. Things are less abstract in implementing each of these concepts that you have asked about.

    The application majorly aims to implement MVC architecture-Model View Controller.

    Each application consists of different Components. AbstractPortalComponent is a Component that renders the functionality at runtime by the Portal Runtime. Everything is written using requests and responses, that is all in code.

    DynPage is a next stage of development in MVC architecture. Here the component and its elements are rendered through HTMLB api. That is in the code itself the HTMLB controls are added to the form and that is added to the component. This has increased the application development consistently.

    The next method is using the JSPDynPage, which enables us to develop, customize the look and feel of the application in the JSP, put the logic and the functionality in a JSPDynPage that renders the component. Thus truly the MVC architecture is implemented.

    a href="http://help.sap.com/saphelp_nw2004s/helpdata/en/8a/4dae42cb9f0f31e10000000a1550b0/frameset.htm"Here/a you can get a clear structure of a component.

    This a href="http://help.sap.com/saphelp_nw2004s/helpdata/en/44/46b9d670e20597e10000000a155369/frameset.htm"tutorial/a might help you in developing applications in whichever method you choose.

    Regards,

    Sujana

  • RELEVANCY SCORE 3.75

    DB:3.75:Difference 7x


    Hi sirs,
    Give me the main differences between abstract class and interface.Dont give me the links sir,

    when we go to use for the interface and for abstract class in developing an application

    DB:3.75:Difference 7x

    Another link:
    {color:#0000ff}http://forum.java.sun.com/thread.jspa?messageID=9961601{color}

    db

  • RELEVANCY SCORE 3.74

    DB:3.74:Re: Interface m8


    Java Glossary : interface vs abstract class
    Abstract classes vs. interfaces: When does it make sense to choose an abstract class over an interface?
    Abstract classes and interfaces practicum: Move from theory to practice on when to employ abstract classes vs. interfaces
    Tech Tips: ABSTRACT CLASSES VS. INTERFACES

    DB:3.74:Re: Interface m8

    I'm still entertained by the fact that some folks will
    spell out words like "multiple", "inheritance",
    "interface", and "implement", but not "because".

    :o)LOL!

    This kills me - just bcuz.

    %

  • RELEVANCY SCORE 3.71

    DB:3.71:Design Question a1


    I have design question.

    I have an interface
    Iabc with two methods: a() and b()
    An abstract class implements this interface with a() implemented,but
    b() declared as abstract method.
    Then i have 3 child classes extending abstract class
    Child1() : inhetis a(), implements b()
    Child2(): inherits a(), implements b()
    Child3(): inherits a(), implements b()

    But if Child1 and Child2 have another common method. then should i put this common method in the interface, implement in abstract class and have empty implementations for it in another child classes that do not need it??
    What are all the different ways of handling this situtation.
    Should i create a new interface or name the abstract class as a just a simple base class, or create a new abstract class...these are some of the question i have....
    Plesae let me know wat is a good implementation and y?

    thanks
    Ragini

    DB:3.71:Design Question a1

    I have design question.

    I have an interface
    Iabc with two methods: a() and b()
    An abstract class implements this interface with a() implemented,but
    b() declared as abstract method.
    Then i have 3 child classes extending abstract class
    Child1() : inhetis a(), implements b()
    Child2(): inherits a(), implements b()
    Child3(): inherits a(), implements b()

    But if Child1 and Child2 have another common method. then should i put this common method in the interface, implement in abstract class and have empty implementations for it in another child classes that do not need it??
    What are all the different ways of handling this situtation.
    Should i create a new interface or name the abstract class as a just a simple base class, or create a new abstract class...these are some of the question i have....
    Plesae let me know wat is a good implementation and y?

    thanks
    Ragini

  • RELEVANCY SCORE 3.70

    DB:3.70:Abstract Class And Interface mc


    From the design perspective what is the difference between Abstract class and Interface.
    If we are providing design, for a system. When should we use abstract class? and when should we use interface.

    DB:3.70:Abstract Class And Interface mc

    And,
    you can only "extends" one abstract class;
    but "implements" several interfaces.

  • RELEVANCY SCORE 3.70

    DB:3.70:Difference Between Interface And Abstract Class a1


    Hi sirs,

    Give me the differences between interface and abstract class
    and when we go for interfaces and abstract class in developing an application

    DB:3.70:Difference Between Interface And Abstract Class a1

    An interface is a 100% abstract class, which means it doesn't contain any code, just method names and signatures. You use abstract classes when you want some code to be shared among the inheritors.

    The advantage with interface is that a class can implement as many interfaces as you like, while it can only extend one (abstract) class.

    So, you use interfaces when you need to extend other classes or doesn't want any code shared, and abstract classes when you don't want to extend other classes, and would like to share some code.

  • RELEVANCY SCORE 3.67

    DB:3.67:What Is The Difference B/W Data Class And Delivery Class km



    Hi,

    1.What is the difference b/w Data Class and Delivery Class?

    2.What is the necessary of Data Element, because without dataelement also we can create one field?

    3.What is the difference b/w Data Element and Domain?

    4.What is the work process?

    DB:3.67:What Is The Difference B/W Data Class And Delivery Class km


    Hi

    1.Delivery class

    The delivery class controls the transport of table data when installing or upgrading, in a client copy and when transporting between customer systems. The delivery class is also used in the extended table maintenance.

    There are the following delivery classes:

    A: Application table (master and transaction data).

    C: Customer table, data is maintained by the customer only.

    L: Table for storing temporary data.

    G: Customer table, SAP may insert new data records, but may not overwrite or delete existing data records. The customer namespace must be defined in table TRESC. (Use Report RDDKOR54 here).

    E: System table with its own namespaces for customer entries. The customer namespace must be defined in table TRESC. (Use Report RDDKOR54 here.)

    S: System table, data changes have the same status as program changes.

    W: System table (e.g. table of the development environment) whose data is transported with its own transport objects (e.g. R3TR PROG, R3TR TABL, etc.).

    The Data class determines in which table space the table is stored when it is created in the database.

    2. yes u can create without refernce to data element

    3. A domain describes the technical settings of a table field.

    A domain defines a value range, which sets the permissible data values for the fields, which refers to this domain.

    A single domain can be used as basis for any number of fields that are identical in structure.

    A data element describes the role played by a domain in a technical context. A data element contains semantic information.

    reward points to all helpful answers

    kiran.M

  • RELEVANCY SCORE 3.65

    DB:3.65:Difference B/W Abstract &Amp; Interface jm


    Anyone tell me what is Difference B/w abstract interface. because i m very confiuse.
    plz tell me

    DB:3.65:Difference B/W Abstract &Amp; Interface jm

    Anyone tell me what is Difference B/w abstract
    interface. because i m very confiuse.
    plz tell meNo doubt you're very confused, seeing how you post this kind of vague-ness.
    http://forum.java.sun.com/thread.jspa?threadID=734360

    Maybe this is the wrong field for you. Just maybe.

  • RELEVANCY SCORE 3.65

    DB:3.65:Difference Between Abstarct Class And Interface 7j


    HI,
    Here is a simple one for the gurus but quite important for me.

    What is the difference b/w an Interface and an abstract class?
    Why do we need each one of them?
    I would appreciate if you people can give examples of each so that I amy understand fully

    Thanks in advance...

    DB:3.65:Difference Between Abstarct Class And Interface 7j

    Sorry about the formatting, this was my first attempt at using [ code ] brackets...

  • RELEVANCY SCORE 3.64

    DB:3.64:What Is The Difference Between Abstract Class And Interface ? dd


    Hi,

    Could u plz tell me the difference between Abstract class and Interface?

    Thanks in advance.

    Gopi

    DB:3.64:What Is The Difference Between Abstract Class And Interface ? dd

    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.

  • RELEVANCY SCORE 3.62

    DB:3.62:Who Can Tell The Difference Of The Abstract Interface Class? xf


    someone ask me that he had a abstarct interface class, such as :
    public abstract interface Book{
    }
    I was comfused, who can tell me why use it?

    DB:3.62:Who Can Tell The Difference Of The Abstract Interface Class? xf

    Cross post - http://forum.java.sun.com/thread.jspa?threadID=694601tstart=0

  • RELEVANCY SCORE 3.57

    DB:3.57:Abstract Class Or Interface ? 11


    can any one tell me the difference between an abstract class an an interface. which is more useful ?

    DB:3.57:Abstract Class Or Interface ? 11

    You could also try searching this site for your question. It has been discussed in other threads as well (I posted a simialar (how do you spell that?) question).

  • RELEVANCY SCORE 3.57

    DB:3.57:Re: What Is The Difference Between An Interface And An Abstract Class? 1a


    8000 views already wow.

    DB:3.57:Re: What Is The Difference Between An Interface And An Abstract Class? 1a

    filestream wrote:
    As the two famous politicians, Jonathan Curry and Larry Craig are wont to say, "Glad I could serve you."

    Of course, each says it in entirely different situations but we're not here to discuss that. The members of the forums are happy just knowing that we've cleared 1 doubt.Now that you mention it, I take a wide stance in the interface/abstract class issue.

  • RELEVANCY SCORE 3.57

    DB:3.57:Abstract Class Vs Interface 9a


    Can somebody please explain to me why we need both abstract classes and interfaces? Don't they serve almost exactly the same role? Besides syntax and the possibility of implementing multiple interfaces, is the only difference that an abstract class is allowed to have non-abstract methods?

    DB:3.57:Abstract Class Vs Interface 9a

    interfaces also may have variables but they have to be declared final. ???

  • RELEVANCY SCORE 3.55

    DB:3.55:Difference j9


    difference between abstract class and interface

    DB:3.55:Difference j9

    @OP You can see by the blatant obviousness and boring repetitiveness of these answers that this is a frequently asked question.

  • RELEVANCY SCORE 3.55

    DB:3.55:Difference Between Abstract Class And Interface 71


    Here is a fresher in Java. Could any body tell me the difference between Abstract Class and Interface. And suppose Abstract class has three methods, in those, two of them are Abstract and one is normal method, and it has been implemented in that class itself. If we extend the Abstract class to our class, do we need to over ride or implement all the methods that are there in the Abstract class or we need to implement only those methods that have been declared as abstract. If it is so, then what is the purpose of implementing non abstract method in the Abstract class.

    Sravan

    DB:3.55:Difference Between Abstract Class And Interface 71

    public abstract class TestAbstract {
    public abstract void method1();
    public abstract void method2();
    public static void method3() {
    // non-abstract method must have a body
    }
    }

    public class TestAbstract2 extends TestAbstract {
    public void method1() {
    // Does not work:
    // Object test = new TestAbstract();
    TestAbstract.method3();
    }
    public void method2() {
    }
    }- you will have to implement all method which are declared as abstract. you do not need to implement method3 in this example., only method1 and method2.
    - an abstract class cannot be instantiated (doesn't work: Object test=new MyAbstractClass())
    - a non-abstract method in an abstract class can be used, if it's a static member.
    - with "extends" you can only have one class, and your class will inherit the members of the superclass
    - with "implements" you can use multiple interfaces, which are only a description of what you have to write yourself...

  • RELEVANCY SCORE 3.54

    DB:3.54:Re: Still Confusing (Difference B/W Abstract And Interface) cz


    pgeuens...Then how could you create a Thread class which must extend some other different class without using Runnable interface?
    I think this is the solution for multiple inheritance.Because sometimes there happen some situations which you are facing this kind of problem. But of course not using multiple inheritance is the best, you are completely right....

    Ayberk Cansever

    DB:3.54:Re: Still Confusing (Difference B/W Abstract And Interface) cz

    georgemc wrote:
    Well, extend is just a keyword.Right. And both "extends" and "implements" ultimately mean "inherits from". In fact both keywords could be replaced with "inherits" and nothing else about the language would change, and it'd still be an accurate description of what goes on.

    Inheritance isn't restricted to implementation re-use, type re-use is still inheritance.A more important aspect of inheritance than implementation. Inheritance is much more about type than about implementation.

  • RELEVANCY SCORE 3.51

    DB:3.51:What Is Difference Between Abstraction And Abstract Class ? j3


    What is difference between abstraction and abstract class ?

  • RELEVANCY SCORE 3.50

    DB:3.50:Difference ???? xz


    What's the difference between an Interface and Abstract class ??????

    DB:3.50:Difference ???? xz

    Is google broken again?
    [http://www.google.co.uk/search?q=What's+the+difference+between+an+Interface+and+Abstract+class] 652,000 hits

  • RELEVANCY SCORE 3.48

    DB:3.48:Abstract Class And Interface???? 39


    hi all, i would like to know the difference between abstract class and interface....could anybody enlighten me on this....

    DB:3.48:Abstract Class And Interface???? 39

    P.S. don't be a loser an put up multiple posts, especially on something so easy to do a search on.

  • RELEVANCY SCORE 3.47

    DB:3.47:Interfaces And Abstract Classes 73


    can anyone pls tell me where exactly an abstract class is used and where exactly an interface is to be used.

    i think the main difference between an abstract class and an interface is that an interface will have all the abstract methods whereas an abstract class can have one or more abstract methods--- if i am not wrong.
    anything to add? -- pls let me know on this....

    and also how they might be useful for us....

    DB:3.47:Interfaces And Abstract Classes 73

    The differences are already quoted. In addition of that
    the abstract class will come in the class/system hierarchy, but interface will not.

  • RELEVANCY SCORE 3.47

    DB:3.47:Difference Between Interface And Abstract Class zm


    What is the differrence between an abstract class and an interace? and when would you use one over the other?

    DB:3.47:Difference Between Interface And Abstract Class zm

    What is the differrence between an abstract class and
    an interace? and when would you use one over the
    other?To (over-)summarise:
    An interface defines what you want to do, but doesn't tell you how to do any of it.
    An abstract class may define some of how to do it, but not necessarily all.

    RObin

  • RELEVANCY SCORE 3.45

    DB:3.45:What Is The Difference Between Abstract And Interface? zd


    Could some one explain what is the difference between abstract class and interface class.

    Lets say I'm creating class why would I choose abstract over interface?

    THanks.

    DB:3.45:What Is The Difference Between Abstract And Interface? zd

    The difference between abstract classes and interfaces is interfaces are defined methods only. In abstract class methods are derived.

  • RELEVANCY SCORE 3.42

    DB:3.42:Difference Between Abstract Classes Vs Interface 77


    Hi,
    Can u pls mention all the differences between Abstract Classes and Interface.? I've mentioned the differences I've known here.

    Known Differences:
    ------------------
    (*) An interface cannot implement any methods, whereas an abstract class can.
    (*) A class can implement many interfaces but can have only one superclass

    Can U pls mention at what situation(practical situation) we've to go for abstract class or Interface?
    Tell me the situation when we have to go for abstract class?
    Tell me the situation when we have to go for interface?

    Please Reply me
    Thanks Regards
    Venkatesh

  • RELEVANCY SCORE 3.41

    DB:3.41:Use Of Abstract And Interface? k3


    when i use Abstract class or Interface.Which one is better?

    DB:3.41:Use Of Abstract And Interface? k3

    Depends on what you want to do. An interface is more general (in that it doesn't define any actual behavior) and allows you to mimic multiple inheritance (a class can implement any number of interfaces whereas it can only extend one class (abstract or otherwise)). Abstract is good if you have a common base of functionality that all of the implementers will be using.

    It's also fairly common to use both (i.e. the interface TableModel and the abstract class AbstractTableModel), so that someone who wants to completely write their own implementation is free to, while someone who wants to just extend or change the standard functionality could do that as well.

  • RELEVANCY SCORE 3.40

    DB:3.40:Difference Between Abstract Class And Interface ca


    Hi everyone,

    CAn anyone explain why the following happen????

    --------------------------------------------------------------------------------
    Abstract class can have a constructor, Interface cannot.
    Abstract class can have static methods, Interface cannot.
    --------------------------------------------------------------------------------

  • RELEVANCY SCORE 3.40

    DB:3.40:Difference Between Interface And Abstract Class 71


    I'm confused on what is the difference of implementing n abstract class and inheriting an interface?

    DB:3.40:Difference Between Interface And Abstract Class 71

    Hi,
    i want to add a few more differences --
    1.The variable defined inside an interface is public, static and final means it's basically a constant,But in case of abstract class you can hide the variable in the implementation class means you can change the value of the variable.

    One very important thing about the these two feature is when to use what?
    Ans:If a group of object is having some common property such that they are not going to be changed over a period then create an Abstract class out of that property.But if only some object is having a common property but not all then create an interface out of that property and implement all that property in Subclass.

    Thanks.

  • RELEVANCY SCORE 3.40

    DB:3.40:Re: Difference Between Abstract Class And Interface 7k


    See reply #44 and then please find something more useful to do.

    DB:3.40:Re: Difference Between Abstract Class And Interface 7k

    Passionate_Java_Lover_Vijay wrote:
    hi tigers,
    i am very new to java.
    i have a doublt iin collection.
    at wht situation what interface wil be best than other.

    where should i use List Set, Map and all.
    Advance thanks 2 guys who help me.

    Thanks
    ThinkGodJebus. Are you for real? Get a grip will you

  • RELEVANCY SCORE 3.39

    DB:3.39:Confusion Between Abstract And Interface a8


    Hi all,
    i'm new to java, can somebody help to explain on abstract and interface method. As i know that abstract or interface does not provide implementation in the superclass and interface class respectively. All the implementation are done in subclass.. why not we use the inheritances and abstract method to solve the problem instead of using the interface... i can't see the difference between the abstract and interface.. can somebody provide me a good example to understand the interface well..

    p/s: pls correct me if i wrong... ;)
    thanks

    DB:3.39:Confusion Between Abstract And Interface a8


    public class abstract Mainclass{
    abstract double area();
    abstract double meter();
    }

    public class Subclass1 extends Mainclass{
    double area(){
    return 5+1;
    }
    }

    public class Subclass2 extends Mainclass{
    double area(){
    return 8+10;
    }
    }Let's say you have
    public class abstract AreaClass {
    abstract double area();
    abstract double meter();
    }And then when you are working on your second iteration and you want to use Dimension class for this purpose for your new code but you want to leave the old code alone. If you have made AreaClass an abstract class, this is impossible.
    public class AreaDimension extends AreaClass, Dimension {
    }will not compile. However if you had defined AreaClass as and interface you can do this:
    public class AreaDimension extends Dimension implements AreaClass {
    double area() {
    return height * width;
    }
    }Then you can pass this to any method that accepts an AreaClass as a parameter and you can also pass it to any method that takes a Dimension.

  • RELEVANCY SCORE 3.39

    DB:3.39:Abstract Class Vs Interface And Importance Of Using xm



    Hi All,

    I want to know what is the difference between Abstract class and Interface.

    and what is the importance of using them.

    Moderator message: please search for available information/documentation.

    Edited by: Thomas Zloch on Sep 27, 2011 1:55 PM

    DB:3.39:Abstract Class Vs Interface And Importance Of Using xm


    Please refer to this thread, already this is discussed in forums

    [ABAP Objects.. Abastract Interface Class;

    Thanks

    Pavan

  • RELEVANCY SCORE 3.39

    DB:3.39:What Is The Difference B/W Abstract Class And Interface j9


    Hi everybody!
    I'm little confused abt the difference b/w abstract class and interface. Plz help me in this regard.
    Bye
    Mustafa

    DB:3.39:What Is The Difference B/W Abstract Class And Interface j9

    You've got a lot of postings describing the semantic differences, here's one that gives you a practical difference: use interfaces to define policy, abstract classes to define mechanism.

    Assuming that got a big "huh?" ...

    An interface defines a set of methods, which I think of as "capabilities." For example, java.util.List defines methods to add/remove/retrieve items to a list. Any object that implements that interface is saying that it has the capability to maintain items in a list. However, it doesn't say anything about how that object is implemented; perhaps it uses an array, perhaps a linked list.

    By comparison, java.util.AbstractList defines at least part of the mechanism used to implement the List interface. It still leaves some of the implementation open to the programmer, but handles a lot of the details common to all lists.

    By keeping this practical definition in mind, I'm not tempted to use an abstract class in place of an interface. Instead, I limit abstract classes to places where there's common implementation -- in other words, they become a refactoring tool.

    One example: as I've started to develop Swing apps, I find that I'm implementing a lot of dialogs. Since I want a common look and feel to my dialogs, there's a lot of code that's common. However, since each dialog has a separate purpose in life, there's also a lot that differs. So I implemented an AbstractDialog class that handles common operations such as UI decorations.

    Now, I could have implemented this as an instantiable class, which would have methods that are overridden by subclasses. But I went with an abstract class for two reasons: (1) there's no reason to instantiate the base dialog, and more important, (2) by defining certain methods as abstract, I force the subclass into providing implementations, thus eliminating bugs due to laziness.

    One last comment: this example defines very little in the way of policy, so it's clearly a candidate to be an abstract class. You may wonder what to do about objects that aren't so clear, but I've found that there are very few of these. In my version of a good OO design, objects either define policy or mechanism, but almost never both.

  • RELEVANCY SCORE 3.39

    DB:3.39:Difference Between Interface And Abstract Interface 8a


    What is the difference between the following?

    interface Sample{

    }and

    abstract interface Sample{

    }Please explain it with an example.

    DB:3.39:Difference Between Interface And Abstract Interface 8a

    An all the interface's methods are public and abstract, even if you don't declare them as such. And all it's variables are public, static final, even if you don't declare them as such.

  • RELEVANCY SCORE 3.39

    DB:3.39:Re: Different Between Abstract Class And Interface 77


    any one can please tell me Difference between
    abstract class and interface. From a typing perspecitive there's no difference (you can declare variables of both). The only difference in principle is that an abstract class also can have concrete methods so it allows you ti inherit implementation along with the type. You can only inherit from one class but from as many interfaces you whish.

    Which one is best ?The short answer is that interface is best.

    DB:3.39:Re: Different Between Abstract Class And Interface 77

    Hi,please kindly help meWell, maybe if you'd post an actual question...

  • RELEVANCY SCORE 3.39

    DB:3.39:Abstract Class Doubt ?? 7k


    what's the difference between the first abstract class and second abstract class .. when and where to use the first type and second type .. Please give me some info on it ...

    First Abstract Class
    public abstract class TestT where T : class
    {

    }

    Second Abstract Class

    public abstract class Test
    {

    }Regards, Gullu.

    DB:3.39:Abstract Class Doubt ?? 7k

    The second class is just a general abstract class - class that cannot be instantiated and is meant to provide common definition of a base class that multiple derived classes can share.
    More about abstract classes on MSDN.
    The first one is a generic abstract class that uses constraints to place requirements on the generic parameter (T). In your case the generic parameter can only be a type that match or inherit from specific base (you call this type 'class').
    e.g.

    public class Testable
    {

    public void Test()
    {
    //some logic here
    }

    }

    public abstract class TestT where T : Testable
    {
    public T t1;

    public void DoWork()
    {
    t1.Test(); //this will work because T must be of type Testable
    }
    }

    More about constraints on MSDN.

  • RELEVANCY SCORE 3.39

    DB:3.39:Difference B/W Abstract Class And Interface dx


    hi friends,

    can anyone plz divulge the differences between abstract class and interface and under what situations can we use these concepts.

    thanks

    madhusudan.D

  • RELEVANCY SCORE 3.39

    DB:3.39:Re: Instanciate Interface cm


    So I suppose I can also assign an abstract class to an interface then.. but
    abstract classes cannot be instanciated...so cant do that right?As you already noticed, abstract classes as well as interfaces can not be instantiated,
    but nothing forbids you to instantiate a concrete class, derived from the abstract
    class or an interface and just refer to it as if it were just the abstract class or
    interface, e.g.interface Something { void doSomething(); }
    public abstract class AbstractSomething implements Something { }
    public class DoesIt extends AbstractSomething {
    public void doSomething() { System.out.println("doing something ..."); }
    }
    ...
    Something a= new DoesIt(); // fine
    AbstractSomething b= new DoesIt(); // fine
    DoesIt c= new DoesIt(); // fine
    Something d= new Something(); // error: can't instantiate interfaces
    Something e= new AbstractSomething(); // error: can't instantiate abstract classkind regards,

    Jos

    DB:3.39:Re: Instanciate Interface cm

    Hi Jos,

    My question was

    so I am assigning the Collection's variable a
    reference to the ArrayList object.or
    Something a= new DoesIt(); // fine
    AbstractSomething b= new DoesIt(); // fine

    I am assigning Something's variable, a reference to
    the DoesIt.... so Somthing hold a reference of type
    DoesIT but it just sounded a little wierd because
    Something was an interface...

    I get it now though... one can assign a variable a
    reference as long as the reference is of a concrete
    class.... even if that variable belongs to an
    interface.Your terminology is really wonky, so it's hard to guage whether you really understand.

    The variables we're talking about here hold references. Those references point to objects.

    The reference variable has an associated type, indicated where it's decleared--Collection, List, String, etc.

    The object that you point the reference variable at must be of a type that is assignment compatible with the declared type of the variable.

    That's all there is to it, unless you're not clear on the rules about assignment compatibility (subclasses, implementing classes, etc.)

  • RELEVANCY SCORE 3.38

    DB:3.38:Abstract And Interface fa


    Dear Sir/Madam,

    Please let me know the difference between Abstract class and Interface.

    DB:3.38:Abstract And Interface fa

    I disappeared as i was checking the forums in javaworld.com, but now i will keep this site as main.

  • RELEVANCY SCORE 3.38

    DB:3.38:What's The Difference Between Abstract Class And Interface? 1z


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

    Thanks.

    Leo

    DB:3.38:What's The Difference Between Abstract Class And Interface? 1z

    Also, you can only extend one class, but can implement many interfaces. I extend a class for true is-a relationships, I use implements like mixins.

  • RELEVANCY SCORE 3.38

    DB:3.38:Java Programming 33


    what is the difference between 'abstract' class and 'interface'

    DB:3.38:Java Programming 33

    Hey, get back in line. Don't jump the queue :)Well I guess I haven't qualified myself for this
    year's hunt. Maybe I could get a free-card because I
    was always on the Most Arrogant List a few years ago.Ok. I'll be nice. You'll get a free pass.

    Kaj

  • RELEVANCY SCORE 3.38

    DB:3.38:Interface Vs Abstract Class d8


    when do we need interface and when abstract class?

    DB:3.38:Interface Vs Abstract Class d8

    2.All the abstract methods must be overrided and
    implemented by the child class.by definition, you can't override a method that has no implementation

    3.Real Examples:

    when we implement the ActionListener interface for
    Button click event then we have to override the
    actionPerformed method, we dont have any other
    chices, so it is a way of forcing the inherited class
    to override certain methods.as before, we implement an abstract method. you're not forcing an override, this can't be done, nor would it be a good idea. as discussed at length recently :-)

    n java you can see all the classes that starts with
    Abstract is abstract.not so. there's nothing at all to stop you writing a concrete class named AbstractClass

  • RELEVANCY SCORE 3.38

    DB:3.38:Instanceof Operator Question sx


    Can you use instance of (successfully) on interfaces and abstract classes?
    I am confused because if class A implements interface B (or extends abstract class B) it is a type of B but it is not an instance of B, since interfaces/abstract classes cannot be instantiated.

    DB:3.38:Instanceof Operator Question sx

    Sorry, the reason I ask is because on weekdays I have limited internet time so if I ask it here I can work on my projects and get the answer without taking time away from working on my project. Thanks for the answers.

  • RELEVANCY SCORE 3.34

    DB:3.34:Abstract Class And Interface z1


    What is most important thing about abstract class and interface.

    When to use abstract class and interface.

    DB:3.34:Abstract Class And Interface z1

    The interface is like an agreement where the class
    which implements the interface promises to write the
    implementation code for all the functions in the
    interface.Same for an abstract class, only, rather than "all the methods" it's "all the abstract methods." Of course, you could turn around and usethat wording for interfaces too, but in that case it means "all the methods" since interfaces' methods are all abstract.

  • RELEVANCY SCORE 3.34

    DB:3.34:Static Methods In Interfaces 3z


    Java cognoscenti,

    Anyone know why I can't declare a method as static in an interface, but I can in an abstract class. Surely, semantically it's the same - defering the implementation of a static method, not an abstract class and an interface. By the way, I'm using JDK 1.2.2 if that makes a difference

  • RELEVANCY SCORE 3.34

    DB:3.34:Abstract Interface ss


    Hi All,
    What is abstract interface?What is the difference between Abstract interface and interface?
    If there is no difference why ServletRequest is abstract inteface.
    Thank You,
    Selvaraj

    DB:3.34:Abstract Interface ss

    Have a look at the JLS Chapter 9.1.1.1 abstract Interfaces
    Every interface is implicitly abstract. This modifier is obsolete and should not be used in new programs

  • RELEVANCY SCORE 3.34

    DB:3.34:Interface Vs Abstract Class 97


    Hi All,
    Here I have a doubt.
    What is the difference between an bInterface/b and bAbstract class/b(Design Point of View)??.
    In which scenario which is useful.
    Can anybody kindly reply me.

    Thanks and Regards,
    Krishna Mattam
    Team Member - CDF Toolset
    Contact:044-22548575
    Email: mkrish17@ford.com

    DB:3.34:Interface Vs Abstract Class 97

    can you pls send the link to that chapter 4.6I haven't seen it online. You probably will have to buy a paper copy. It's published by Sun. It's the authorative reference on Java so it's worth having.

  • RELEVANCY SCORE 3.33

    DB:3.33:Difference Between A Abstract Class With 4 Abstract Methods And A Interface With 4 Abstract Methods. 8c


    what is the difference between Difference between a Abstract class with 4 abstract methods and a Interface with 4 abstract methods.

    DB:3.33:Difference Between A Abstract Class With 4 Abstract Methods And A Interface With 4 Abstract Methods. 8c

    Your question is better rephrased as: What is the difference between an abstract class and a interfase?
    This has been discused here
    http://social.msdn.microsoft.com/Forums/en-US/csharpgeneral/thread/67451957-f0bd-4b9b-a2c0-16f604ce8643
    Regards

  • RELEVANCY SCORE 3.32

    DB:3.32:Diff Between Interface And Abstract Class 9a



    Hi to all,

    I am woking on OOP in ABAP .Could any one can tell the difference between interface and abstract class.

    thanks in advance .

    DB:3.32:Diff Between Interface And Abstract Class 9a


    Hello Sagar,

    like Uwe told one basic difference is that you may provide some methods with an abstract class but not with an interface. The unique feature of interfaces is that you may implement several ones while abstract classes are limited to one inheritance hierarchy.

    Regards

    Klaus

  • RELEVANCY SCORE 3.32

    DB:3.32:Abstract Class And Interface 7x


    Hi,
    This is ramana, I got a doubt
    1. I have one interface
    interface Intabs {
    abstract void method1();
    abstract void method2();
    abstract void method();

    }
    2. Iam trying to convert that interface into abstract class like below
    interface Intabs {
    abstract void method1();
    abstract void method2();
    abstract void method();

    }
    3. Again iam trying to extend that abstract class into class like below
    interface Intabs {
    abstract void method1();
    abstract void method2();
    abstract void method();

    }

    Iam getting errors

    Can i do it in multiple steps: Interface------abstract class----- class

    DB:3.32:Abstract Class And Interface 7x

    Cannot reduce the visibility of the inherited method
    from IntabsDerabst1.java
    Right. As mentioned, you can't assign weaker access priveleges to inherited methods. If you define a method as "public void foo() {}", the "foo()" method must have at least public access in all subtypes. In your example, your interface methods are public, but you're trying to give them "package-private" (default) access in the abstract and concrete implementation classes.

    ~

  • RELEVANCY SCORE 3.32

    DB:3.32:Re: Difference Between Abstract Class And Interface. f3


    Thanks, jverd. I have got it.

    George

  • RELEVANCY SCORE 3.32

    DB:3.32:Abstract Class &Amp; Interface 17


    What is the difference between Abstract Class and Interface Class? What I understood is both has to be defined in the subclass i.e methods. Apart from that Interface supports multiple inheritance whereas Abstract class doesn't. When both has to be defined in the subclass and interface supports multiple inheritance why we still need Abstract Class.

    Thanks in Advance,
    R.Ravindhran

    DB:3.32:Abstract Class &Amp; Interface 17

    A class can only extend one other class (Abstract or not) but it can implement any number of interfaces.

  • RELEVANCY SCORE 3.31

    DB:3.31:Difference Between Abstract Interface And Normal Interface za


    Hello Friends,

    What is the Difference between abstract interface and normal interface?....

    DB:3.31:Difference Between Abstract Interface And Normal Interface za

    What is the Difference between abstract interface and
    normal interface?....The difference is that you didn't follow convention in the first case. All interfaces are implicitly abstract so you don't have to declare them as such.

  • RELEVANCY SCORE 3.29

    DB:3.29:Abstract Class Vs Interface 9d


    Hi

    I was just wondering what is the advantage of using an abstract class over interface. In what situation, using an abstract class is more suitable than using interface? and vice versa?

    DB:3.29:Abstract Class Vs Interface 9d

    This question has been asked and answered a million times. For instance, see this thread: http://forum.java.sun.com/thread.jsp?forum=31thread=352322

  • RELEVANCY SCORE 3.29

    DB:3.29:Best Situation That Describe Difference Between Interface And Abstract c7


    Hi, Please tell me the best example or situation where we should choose interface or abstract class?

    DB:3.29:Best Situation That Describe Difference Between Interface And Abstract c7

    Smiley,
    It is the same as about apples and computers.
    An Interface is a contract, it describes what a class should contain to implement it (and can than be used to to get those members of a class whichfulfillthe contract) but an interface contains no actual implementation.
    An Abstract Class is a class itself which can be (only) inherited used as base for another class, the members and properties of a base class can be used likewise the inheriting class.
    Because of above can an Abstract Class implement an Interface, however an Interface cannot implement an Abstract class.

    Success
    Cor

  • RELEVANCY SCORE 3.28

    DB:3.28:Interface And Abstract Class ad


    Why can't we declare a static method in Interface but it's possible in abstract class?

    DB:3.28:Interface And Abstract Class ad

    Because an interface is simpler than an abstract class.
    Normally you would put a static method like this into a utility class with a private constructor. see the Math class.

  • RELEVANCY SCORE 3.27

    DB:3.27:What Is The Main Difference B/W Interface And Abstract Class 83


    is there any specific difference b/w interface and abstract class. if wht is tht? and how?

    DB:3.27:What Is The Main Difference B/W Interface And Abstract Class 83

    abstract class can be have methods with body

    interface cannot

    interface is 100% abstract class

  • RELEVANCY SCORE 3.27

    DB:3.27:Difference % Abstract Class And Interface? d3


    Hi,

    I am confused about abstract class and interface. For interface, the subclass has to implement all the parent class methods. But, it is no need in abstract class.

    However, in which situation should I use abstract class or interface?

    Thanks for explanation.

  • RELEVANCY SCORE 3.26

    DB:3.26:Difference B/W Factory Pattern Abstract Factory Pattern ? 88


    Hi friends,
    Can anyone tell me what is the difference between factory pattern and abstract factory pattern ? I know how to implement factory pattern...
    Thanks!!
    MCP

    DB:3.26:Difference B/W Factory Pattern Abstract Factory Pattern ? 88

    Factory pattern violates OCP while Abstract Factory doesnt
    I tried to think about 3 factories here:factories from simpledesignpatterns
    Please, share Your thoughts there
    Thanks,
    Efim

  • RELEVANCY SCORE 3.25

    DB:3.25:Interface And Abstract Class Difference 18


    An interface can be used in such a way that we don't know the class of object assigned to a reference of that interface type until runtime. Can we use the abstract class in a similar way too?

    The difference between an abstract class and interface can be listed as
    1. Interface can not have implementation of any method
    2. The usage of interface and class is one other difference
    3. What other differences we have?

    DB:3.25:Interface And Abstract Class Difference 18

    941767 wrote:
    Here we have some more difference...Differences that mean nothing to an experience professional programmer.

  • RELEVANCY SCORE 3.24

    DB:3.24:Regarding The Abstract And Interface km


    hai,
    I am new to java programming

    I want to difference between abstract interface,interface and abstract class

    public abstract interface Test{}

    public interface Test{}

    public abstract class Test{}

    which kind of situations use the above interfaces and abstract classes

    It would be helpfull if explain with example....

    Thanks

    DB:3.24:Regarding The Abstract And Interface km

    shashikumar, please don't multipost and don't use the browser's back button to edit your post. This creates multiple posts. I've removed the other thread you started a minute after this one.

    db

  • RELEVANCY SCORE 3.23

    DB:3.23:C#: What Is Difference Between Abstract Class And Interface? How To Decide To Use Which One? 18


    I have been asked a question: how to decide to use Abstract class or Interface?
    We know that the Interface is special Abstract. All definitationsare default public and without implemetion. Classed inherit from interface has to implement all definitions.

    Abstract class does not need to implement all the methods and it can not be instantiated.
    Classes inheritfrom abstract classmay sharecommon logic (properties or methods) with abstract class and also override some methods' behavior.
    How to clearily answer this question? Thx!

    JaneC

    DB:3.23:C#: What Is Difference Between Abstract Class And Interface? How To Decide To Use Which One? 18

    Hello JJChen,
    Interface class can be implement in small units of data but abstraction class can be implemented in large units of data.
    1. Here is explanation of
    Interface class
    2. Here is explained
    Abstraction class.
    3.
    Difference betweenAbstraction andInterface class.
    Hope it will help you a lot.
    thanks,

  • RELEVANCY SCORE 3.22

    DB:3.22:Differance Between Abstract Class And Interface 7s


    Whats the main differance between abstract class and Interface and where I can use abstract class and where I can use Interface

    DB:3.22:Differance Between Abstract Class And Interface 7s

    Refer to
    http://www.javaworld.com/javaworld/jw-09-2001/jw-0921-interface.html

  • RELEVANCY SCORE 3.22

    DB:3.22:Abstract Class And Interface Having Same Method fa


    Hello,

    Here is my problem. Suppose we have one abstarct class and one interface.Here is code-
    //Abstarct class
    abstract class X{
    abstract void myMethod();
    }

    //Interface
    public interface Y{
    abstract void myMethod(){}
    }

    Now i have a class which extends both abstarct class X and interface Y.
    If i call myMethod() from this class. Whose myMethod would be called.Will it be of abstract class or interface?
    Many Thanks

    DB:3.22:Abstract Class And Interface Having Same Method fa

    Oops, last part should be

    Now, let's pretend the abstract class above did have code in it.
    //Abstract class
    abstract class X {
    void myMethod() { System.out.println("Hello"); }
    }
    Then, you wouldn't have to have a myMethod() implementation in your class which extends X and implements Y (it's defined in X). If you didn't have one, the method in X would run. If you defined your own myMethod() implementation in your class (which extends X and implements Y), then your own implementation would run.

  • RELEVANCY SCORE 3.21

    DB:3.21:Abstract And Interface? cm


    why do we need abstract class?
    why do we need interface in java?

    DB:3.21:Abstract And Interface? cm

    Oh please, do some research of your own.

  • RELEVANCY SCORE 3.21

    DB:3.21:Difference Between Abstract Class And An Interface 3z


    Hi,
    Can any one pls define that what is exactly difference between an Abstract Class and an Interface? Also I'll appreciate if some one can tell me that what we should prefer to use and why.
    Waiting for reply,
    Pranav

    DB:3.21:Difference Between Abstract Class And An Interface 3z

    Hm, it shows some uses but it (and it's predecessor article) actually don't tell what an abstract class or an interface is (or I overlooked it :-)

    Abstract class
    An abstract class is a class which can be declared and used to derive from, but which is not possible to instantiate.

    Like Animal - there is no animal, but there are Goldfish or Cat. Thus you want no Animal objects roaming your heap but only Goldfish and Cat instances. Still it makes sense to bundle the common features in Animal, and distribute them per inheritance.

    Interface
    While a class allows to group functions and variables into a unit, an interface only allows to group functions.
    Otherwise it is the same, thus can be derived from.

    However it makes no sense to create different instances of this, because you can't seperate them, there is no variable which would hold different state information that could be used for a comparison with nonequal result.

    Java offers the multiple inheritance from interfaces only, not from classes.
    This is a simplification chosen by the language designers to keep the implementation algorithms for the tools, the VM, the memory layout of the VM and perhaps the semantics complexity simple.
    (Java was intended for remote controls and other embedded devices).

    Why is this simpler?
    If A inherits from B and A inherits from C as well.
    Plus B inherits from D, plus C inherits from D,
    then we have no longer a tree/directed acyclic graph,
    but the more general case of a directed graph.

    This makes algorithms more complicated (tree walk is easier than graph walk, where you have keep track of cycles).

    Further instantiation make more trouble.
    An instance of A would contain two instances of D, one along the path A-B-D, and one along the path A-C-D.
    Thus if B,C,D were classes with variables, B-D's variables might be different from C-D's.
    This makes access semantics and storage much more complex.

    Java simplified this problem by avoiding it by just allowing interfaces for B, C, D.
    Calling A-B-D-f() is the same as calling A-C-D-f().

    Regards,
    Marc

  • RELEVANCY SCORE 3.21

    DB:3.21:Use Of An Abstract Keyword 37


    Hi all , I want to know about

    1.the usage of an abstract keyword.

    2.Difference between abstract and interface

    3.When to use abstract keyword.

    DB:3.21:Use Of An Abstract Keyword 37

    Hi all , I want to know about Give it a try yourself first, post it here and you get feedback.

  • RELEVANCY SCORE 3.20

    DB:3.20:When To Use Abstract Class And Interface? jp


    hi,

    When to use Abstract class and Interface?

    DB:3.20:When To Use Abstract Class And Interface? jp

    Thanks for all, i got some clear idea about when to use interface and abstract class.

  • RELEVANCY SCORE 3.20

    DB:3.20:Hi Friends s7



    can u tell me what is difference b/w conversions and interface

    DB:3.20:Hi Friends s7


    Hi

    Conversion: Whenever there is need of loading legacy data(huge data at a time) into current SAP system, we call it conversion. Baically it is one time effort. Once all the data has been loaded(during go-live) we dont need them anymore.

    Interface: These are used everyday. for eg. a company receives invoices via EDI(or some other channel) everyday. You develop interfaces to load these invoices into your system from time to time. It should be noted that this is a process that happens everyday and you will need them for ever.

    Interface: it is a program that performs communication with External system from SAP.

    There are two types of interfaces:

    1. Inbound Interface: External system sends the data to SAP

    2. Outbound Interface: SAP sends the data to External system.

    Let's take a scenario:

    There are two Systems SAP ERP and Seibel CRM

    Scenario1: Whenever an Order is created in Seibel CRM system it has to be transferred to SAP where the Order confirmation, Delivery and Billing will be performed. This can be enabled by using IDOC as inbound interface.

    Scenario2: Whenever a New customer is Created in SAP ERP this customer data has to be transferred to Seibel CRM using Outbound IDOC / RFC.

    Basically interfaces are implemented using RFC, BAPI, ALE/IDOC.

    INTERFACE programs are the ones which are run at regular intervals, say weekly, monthly or even daily. Here the legacy system continues to co-exist along with SAP system, the legacy system might be useful for certain functionalities but the data might have to run thru SAP transactions for complex data maintenance at regular intervals.

    Interface Program

    http://help.sap.com/saphelp_erp2005/helpdata/en/64/be5b4150b38147e10000000a1550b0/frameset.htm

    Conversion:

    Migration of data from Legacy system before GO Live (One time data transfer).

    So Conversions are always INBOUND interfaces.

    Conversions are performed using Batch input(BDC), LSMW and BAPI.

    CONVERSION programs are the ones which have one time usage, usually when a legacy system is being replaced by a system like SAP, then the data has to be mapped from the legacy system to SAP system. Here the data to be converted is given on a flat file is uploaded to SAP tables mostly using LSMW only. Conversions programs are BDC,BAPI and LSMW programs in which you upload all the related tables from the flat files.Those are one time programs.

    Interface programs are those programs in which you fetch the data from the application server and process on theose data.These are helpful when you have to run any program in the backgroup when the presentation server is not working.

    Conversion Program

    http://help.sap.com/saphelp_erp2005/helpdata/en/d3/a65a14e96911d1b401006094b944c8/frameset.htm

    In Simple

    CONVERSIONS : Converting Legacy System DATA into a flat file

    INTERFACES : Converting Flat File into SAP

  • RELEVANCY SCORE 3.19

    DB:3.19:Assigning Object To Interface Type And Abstract Class Type. pm


    Can any one please tell me what is the difference between assigning the object to Interface type and abstractclass type instead of assigning to class type except that, if we assign an object to interface or abstractclass type, then we can access only the methods available in interface or abstract class.
    Code:
    Class cls = new Class();

    // Need Difference between the following

    Interface inf = new Class();
    AbstractClass abscls = new Class();Thankyou,
    Ram

    DB:3.19:Assigning Object To Interface Type And Abstract Class Type. pm

    Note: This thread was originally posted in the [Reflections Reference Objects|http://forums.sun.com/forum.jspa?forumID=4] forum, but moved to this forum for closer topic alignment.

  • RELEVANCY SCORE 3.18

    DB:3.18:Abstract Class And Interface 3j


    I would covet to recognize at what situation we use abstract class
    and when to use interface?

    With Regards,
    Stalin.G

    DB:3.18:Abstract Class And Interface 3j

    http://www.google.com/search?q=abstract+class+interface+site:forum.java.sun.com

  • RELEVANCY SCORE 3.17

    DB:3.17:Inter Face And Abstract Class c3


    hi
    can u please tell me the difference between interface and an abstract class? In which situations they will be usefull.
    thank u
    shyam

  • RELEVANCY SCORE 3.17

    DB:3.17:Concept Of Abstract Class &Amp; Interface fc


    Hi friends,

    My question is what is the main difference between Abstract class Interface?

  • RELEVANCY SCORE 3.16

    DB:3.16:Interface And Abstract Class c8


    Hi,

    Could you please let me know what is the exact difference between interface and abstract class.Which one is better to use .Could you please give me indepth answer.

    DB:3.16:Interface And Abstract Class c8

    Stop. Stop. Stop. I beg you...You're behaving like a Chinese gentleman with sand in his boots. Stop.

    Do we save the execution time by using interface.This is a compiler/byte code related question. Please post it in the proper place.

    What might be the behaviour inside the memory
    location by using interface and abstract class.Same answer.

    /Morten

  • RELEVANCY SCORE 3.15

    DB:3.15:Difference Between Abstract Class And Interface ? fz


    CAN ANY BODY TELL ME THE DIFFERENCE BETWEEN THE ABSTRACT CLASS AND INTERFACE ?

    DB:3.15:Difference Between Abstract Class And Interface ? fz

    - An abstract class is a class that can not be instantiated but that can contain code, i.e. it gives you the ability to specify default implementations of methods.

    - An interface only contains methods but does not contain any code and you need to implement all the methods defined in the interface.
    - Interfaces may be multiple-inherited, abstract classes may not
    http://www.codeproject.com/Articles/11155/Abstract-Class-versus-Interface
    http://stackoverflow.com/questions/56867/interface-vs-base-class

  • RELEVANCY SCORE 3.15

    DB:3.15:Good Simple Example Of Difference Between Interface And Abstract Class 83


    Hi All,

    I am new to java...

    I am confused lot about the difference between interface and abstract class....

    Can anybody tell me the difference between interface and abstract class with some good and simple exmple...

    Kindly help me...

    Thanks in advance...

    DB:3.15:Good Simple Example Of Difference Between Interface And Abstract Class 83

    phdk wrote:
    georgemc wrote:
    public class AbstractClassThatIsntAnInterface {

    public abstract void doSomething();
    public abstract void doSomethingElse();

    }Nice naming for a nonabstract class! ;-)

    @OP: read this: [http://java.sun.com/docs/books/tutorial/java/IandI/abstract.html]Er, you, um, spotted my deliberate mistake.....

  • RELEVANCY SCORE 3.15

    DB:3.15:Re: Abstract Class Vs Interface Difference jc


    While this is by no means complete, the major
    differences between an interface and an abstract
    class with all abstract methods is that you don't
    have to create an implementation for the abstract
    methods in a class that extends the abstract class.Yes you do; unless the extending class is also abstract.

    You do have to implement all methods in an
    n interface. Also you can use access modifiers other
    than public in an abstract class, while interface
    methods must always be public. public or package-private?

    If you don't know why either of these things would be useful then you
    probably don't care, and could just use an interface.And seeings as people are answering here desipte the laziness; abstract classes can also have implemented methods, and member variables. Interfaces cannot.

    DB:3.15:Re: Abstract Class Vs Interface Difference jc

    While this is by no means complete, the major
    differences between an interface and an abstract
    class with all abstract methods is that you don't
    have to create an implementation for the abstract
    methods in a class that extends the abstract class.
    You do have to implement all methods in an
    n interface. No.

    The rules for what must be implemented are the same regardless of whether it's a class or an interface.

  • RELEVANCY SCORE 3.15

    DB:3.15:Abstract Classes Interface ? kd


    Hello

    I wonder if anyone could help me to stright out my big questionmark regarding Abstract classes and Interfaces by answering following questions.

    1) When and why should I use Abstract classes, an real life example would be very appreciated. I have been programming for a while but I have never created an Abstract class.....

    2) Whats the difference in using Abstract classes and an interface when both of them explains whats are needed. Is an interface just an design pattern that points out which methods that are required so this particulare class should be working or correctly or?

    Thanks!

    Regards /D_S

    DB:3.15:Abstract Classes Interface ? kd

    Please search the forum or google. This has been asked, and answered about 8928911 times before.

    Kaj

  • RELEVANCY SCORE 3.15

    DB:3.15:What Is The Difference Between Abstract Class And Interface af


    hi,recently i went for an interview they ask me what is abstract class ,interface and its difference
    I said abstract class contain abstact method ,abstract method is a method with no body.Abstract class cannot be instantiated.Abstract class is a base class it required derived class for the implementation of method.
    Interface is a syntactical contract that all derived class should follow
    it define properties ,method,events which are known as member of interface.
    Then They asked me what is the difference between them. I said
    abstract class interface
    1.abstact class can implement method 1.interface cant
    2.abstact class can contain constructor, 2.interface cant
    destructor
    3.abstract class cannot support multiple 3.interface support
    inheritance
    etc
    Then they said some different answer I said dont no.
    Then they ask me when i should make abstract class for an project and when
    i should make interface.
    I said if suppose there is two class which must be having method with different logic then we sholud make abstract class.
    and if suppose we have two class having method .with different logic then we can make interface .
    Am i correct with my explaination.if not correct me .please provide me that when should we create abstract class and interface and what is difference .please help me

    DB:3.15:What Is The Difference Between Abstract Class And Interface af

    I would focus the answer on the distinction that you cant add an abstract class to an existing class like you can an interface.

  • RELEVANCY SCORE 3.15

    DB:3.15:Help With Interface And Abstract cs


    Hi all

    what is the difference between an interface and an abstract class??

  • RELEVANCY SCORE 3.14

    DB:3.14:Abstract Class And Interface Use 1k


    hi

    i am asking some stupied questions. plz can any one tell me

    1) what is interface and abstract class ? one example?
    2) when do u go for interface and when do u go for abstract class?
    3) what is exact difference between abstraction and encapsulation?

    thanks in advance

    DB:3.14:Abstract Class And Interface Use 1k

    Mahaboob wrote:
    hi

    i am asking some stupied questions.I agree.

    plz can any one tell meHere's a much better idea. You go do some basic research on these questions which have been asked 1,000,000,000 times previously and then tell us what you think. Then we can have a lively discussion about your ideas.

    'kay?

    And just to get you started in the right direction here's something you can review that will answer part of or all of your questions [_http://java.sun.com/docs/books/tutorial/java/index.html_|http://java.sun.com/docs/books/tutorial/java/index.html]

  • RELEVANCY SCORE 3.14

    DB:3.14:Difference Between Abstact Class And Interface fk


    hi

    i am new in java.

    plz tell me abstract class support which type of polymorphisam and
    interface support which type of polymorphisam
    plz explain

    bye
    siva

    DB:3.14:Difference Between Abstact Class And Interface fk

    There's only one type of polymorphism.

    Does that make it mono-polymorphism? ;)

    Indeed - do a search for the forums.

    The short answer is that both abstract classes and interfaces define required method signatures for subclasses that extend/implement them, but abstract classes can have implementation for some or all methods that are not abstract; interfaces have no implementation whatsoever for any methods.

    %

  • RELEVANCY SCORE 3.14

    DB:3.14:Interface And Abstract Class c3


    why we have constructor for abstract class and not for interface,

    DB:3.14:Interface And Abstract Class c3

    http://forum.java.sun.com/thread.jspa?messageID=10174604

    Double your pleasure or not!

  • RELEVANCY SCORE 3.13

    DB:3.13:Interfaces And Abstract Classes 8x


    Whats the difference between an interface and an abstract class.

    DB:3.13:Interfaces And Abstract Classes 8x

    Another trait that is often overlooked is that the abstract methods and constants declared in an interface are always public; with abstract classes, you can declare them (package) and protected scope as well.

  • RELEVANCY SCORE 3.13

    DB:3.13:Abstract Class And Interface 97


    is it any differences between abstract class and interface?

    DB:3.13:Abstract Class And Interface 97

    And of course you [url http://onesearch.sun.com/search/developers/index.jsp?col=devforumsqp_name=Java+Programmingqp=forum%3A31qt=%22+differences+between+abstract+class+and+interface%22] searched first....

    Mike

  • RELEVANCY SCORE 3.13

    DB:3.13:Simple Query ac


    Difference between Abstract class and interface with practical example

    DB:3.13:Simple Query ac

    You are right; it was a simple query. (and I don't mean "simple" as in lacking complexity.)

  • RELEVANCY SCORE 3.12

    DB:3.12:Interface cf



    Hi..

    What is the difference b/w classes and interface

    DB:3.12:Interface cf


    The essential difference between interfaces and classes is that there is no implementation part for an interface. Therefore, it is not necessary to add DEFINITION to INTERFACE. The methods of an interface are all abstract. They are fully declared, including their parameter interface, but not implemented in the interface. Like the subclasses that implement the abstract methods of their abstract superclasses, all classes that want to use an interface must implement its methods.