• RELEVANCY SCORE 4.84

    DB:4.84: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:4.84: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 4.14

    DB:4.14:Abstract Inteface 87




    What is the difference between Abstract interface and interface ?
    if there is no difference,why ServletRequest ,etc are abstract interface.
    Thanks
    Selva

    DB:4.14:Abstract Inteface 87

    SelvaBalaji wrote:
    in the eclipse have opened the interface.and where did eclipse get it from? Remember that it doesn't really matter at all and so we should probably spend our time learning more useful stuff.

  • RELEVANCY SCORE 4.14

    DB:4.14: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 4.13

    DB:4.13:Difference Between Interface And Abstract Class mj


    hello friends give me the difference between interface and abstract class
    and link to find java material

    Thanx

  • RELEVANCY SCORE 4.11

    DB:4.11:Re: Abstract Class With All Abstract Methods Is Same As Interface ?. ff


    kogose wrote:
    this looks ambiguous to me?Have you tried it? The compiler will tell you that it's ambiguous and won't let you compile it.

    DB:4.11:Re: Abstract Class With All Abstract Methods Is Same As Interface ?. ff

    An abstract class with all abstract method is not equal to an interface.

    An abstract class is just like any other class, only that it cannot be instansiated. In order to use the methods and data, it has to be extended.
    An interface on the other hand, defines a set of prototype.

    If i knw what interface you are implementing, i dont have to know what code you have written in the function. It is more like standardising. But when you write an abstract class, and i am using it, in future you may change its contents and add things that is not necessary for my program. An interface implemented, helps the other programmer to know how to access a perticular functionality of a class.

    For example, if i want to access a functionality draw() from your class, say circle, i just have to knw its signature. If you are using an interface and implementing the function of that interface, in future you cant change the signature of the function (can change the content thou) . But when it comes to abstract class, you can overload and override, in which case you may change the signature (as you have the descrition), and my program may no longer be able to use your draw() function. Thus, consistency is questioned. Interface avoids such a problem.

  • RELEVANCY SCORE 3.97

    DB:3.97:1) Interface 2) Response.Sendredirect And Jsp:Forward am


    Hi Frens

    I got few questions to clarify..
    1) Why we have interfaces and abstract classes both? What are the advantages of interface?
    Whatever the abstraction I want I can implement in Abstract class na! Then why interfaces are needed?
    Like the example...

    interface Ai {
    void method1();
    void method2();
    }
    class Ac extends SomeClass implements Ai {
    void method1 {
    //some implementation
    }
    void method2() {
    //some...
    }
    }
    Now I can design this without using interface also right?

    abstract class Aa extends SomeClass{
    abstract void method1();
    abstract void method2();
    }
    class Ac extends Aa {
    void method1 {
    //some implementation
    }
    void method2() {
    //some...
    }
    }
    Like this I can do with abstract classes also na! Then why interfaces are needed?
    plz give except the answer - "for Implementing Multiple Inheritance in java", say other. :)

    What is alternative for interface in C++?

    2) what is the exact difference between
    jsp:forward and
    response.sendRedirect and
    RequestDespatcher rd = new RequestDespatcher(URL);
    rd.forward()
    Which is preferred? when? why?
    Why there are 3 ways? cant one among them suffice?

    Hope Im clear.. If not mail me I'll clarify regarding this qns. :)

    DB:3.97:1) Interface 2) Response.Sendredirect And Jsp:Forward am

    1. Ever tried extending 2 abstract classes?

    2. Read the API.

  • RELEVANCY SCORE 3.89

    DB:3.89:Abstract Class And Interface fk


    Hi,
    Can any one explain in simple words
    what is the use of abstract class and interface
    and when we have to use abstract classes and interface
    thanks you

    DB:3.89:Abstract Class And Interface fk

    We use abstract class when their is commonbehavioramong the classes. In order to enforce , some default functionality to classes which are getting derived from the abstract class , use abstract class.
    But Interfaces are use to provide only the contracts for the classes which are not relating to each other. we are enforcing some features to the classes which are implementing the interface , but the implementation varies for the classes.
    Lalit
    Propose it for answer if solves your query.
    Lalit

  • RELEVANCY SCORE 3.89

    DB:3.89:Interface Vs Abstract Class sz


    Let say that an abstract class has all abstract functions and someone use it instead of interface.
    What are the disadvantage and advantages?
    I know one that he cannot do multiple inheritance, hence he cannot extends abstract class and use any other parent Class. However, I wish to know more disadvantage/advantages.

    Looking forward for your input.

    --
    PS: I know interface cannot have code and abstract class could have code (non-abstract) methods.

    .

    DB:3.89:Interface Vs Abstract Class sz

    HowToDoIt wrote:
    Let say that an abstract class has all abstract functions and someone use it instead of interface.
    What are the disadvantage and advantages?
    I know one that he cannot do multiple inheritance, hence he cannot extends abstract class and use any other parent Class. However, I wish to know more disadvantage/advantages.

    Looking forward for your input.

    --
    PS: I know interface cannot have code and abstract class could have code (non-abstract) methods.

    .An Interface expresses a contract.
    A class implementing an interface is saying "I will supply implementations of all methods described in the interface, i.e. methods with those particular signatures"

    A class can of course implement multiple interfaces, i.e. it is capable of fulfilling multiple contracts.

    An Abstract class is used to provide a 'base' implementation of some specific functionality (whether it is described in an Interface or not).

    I cannot think of a useful purpose for an abstract class that contains only abstract methods (perhaps it inherits some behavior from its base class)

    Usually some methods in an abstract class WILL be implemented, either because they are unlikely to change in child classes, or they provide a guide/example of implementation, or the implemented methods may be defined in terms of some of the abstract methods, this allows classes which extend the abstract class to 'mix in' their behavior with that of the base abstract class.

    So Interface and Abstract Class have two distinct and separate purposes.

    I hope that is clear?

    Just to help with the details, you can put more than just method signatures in an interface, your could for example have in your interface

    public interface Face1
    {
    public static final int x = 3;
    }which you would access as:

    int fred = Face1.x;And you can place a public static class inside of your interface, the methods of which you would access in a similar way, but you should avoid this unless you really know what you are doing.

  • RELEVANCY SCORE 3.86

    DB:3.86:Re: What Is The Difference Between An Interface And An Abstract Class? 1a


    8000 views already wow.

    DB:3.86: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 3.80

    DB:3.80:Why Interface?Differnce Between Interface And Abstract Class d3


    why we go for interface? what is the difference between interface and abstract class?

    can anyone plz explain with clear picture.

    DB:3.80:Why Interface?Differnce Between Interface And Abstract Class d3

    Look at his profile. He's nothing but a homework dumper anyway. Someone to be ignored.

  • RELEVANCY SCORE 3.79

    DB:3.79:Regarding Abstract And Interface xj


    When sholud i go for abstract class and when sholud i go for interace and which one will prefer when we are doing project...?

    DB:3.79:Regarding Abstract And Interface xj

    hi,
    plz go through the following link, u may get some useful information.

    http://www.sap-img.com/java/when-we-go-for-abstract-and-interface.htm

  • RELEVANCY SCORE 3.78

    DB:3.78: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:3.78: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 3.77

    DB:3.77: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:3.77: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 3.77

    DB:3.77:Abstract Class Needs To Implement Interface ms


    Hello, I have an interface and base abstract class defined as follows: interface IbusinessInterface{    void DoSth1();    void DoSth2();    void DoSth3();    void DoSth4();    void DoSth5();    ...    ...    void DoSthN();}public abstract class BaseClass : IBusinessInterface{    public abstract void DoSth1();    public abstract void DoSth2();    public abstract void DoSth3();    public abstract void DoSth4();    public abstract void DoSth5();    ...    ...    public abstract void DoSthN();} what is the reason that this abstract class needs to have methods of the interface implemented  ?Thanks, Michal

    DB:3.77:Abstract Class Needs To Implement Interface ms

    Look at the other side of the coin!  Think interface contract.  The abstract base class is NOT defining any default implementation for you.  Now, when you browse the abstract class you can SEE the member methods that are or not implemented without having to look any further.  Also, when the members of the abstract class are declared as abstract the IDE can generate method stubs for you automatically!  That does not happen if they are declared as virtual.

    Mark the best replies as answers. Fooling computers since 1971.

  • RELEVANCY SCORE 3.77

    DB:3.77:Re: Interface Vs Abstract Class 1d


    Abstract classes have the significant advantage that you don't have to change each and every implementation if you add a new method with a sensible default implementation.

    DB:3.77:Re: Interface Vs Abstract Class 1d

    You cannot tighten a screw with a hammer. You break
    the threading, and it will remain loose.But it's very hard to hit broken things repeatedly in a satisfying manner with a screwdriver in such a way that the thing in question is not recognizeable as what it was to begin with. Granted, it's possible but rather hard to do with a screwdriver ;-)

  • RELEVANCY SCORE 3.77

    DB:3.77:Difference Between Pure Abstract Class And Interface? 89


    hi,
    i just want to know the difference between pure abstract class(as same as interface- no implementation of methods) and interface

    Thanks,

    DB:3.77:Difference Between Pure Abstract Class And Interface? 89

    A very nice and detailed article on this code project link (posted by Magnus).

  • RELEVANCY SCORE 3.76

    DB:3.76:Difference Between An Interface And An Abstract Class 9f


    Hey:

    I'm curious, what's the difference between an interface and an abstract class? Thanks.

    DB:3.76:Difference Between An Interface And An Abstract Class 9f

    "You have an abstract class if you want to implement some of the methods in it, but you do not want users to make instances of the class or do not want to implement all of the methods. Take a look at some of the abstract classes in java.util. Nearly all of the methods are implemented already so that it's far easier to create new data structures than if only interfaces were provided. "

    That's what I was looking for. Thanks.

  • RELEVANCY SCORE 3.75

    DB:3.75:Abstract Class With Abstract Methods Only p7


    Hi,

    What if you had an Abstract class with only abstract methods? How would that be different from an interface? In such case which needs to be chosen?
    I know that abstract class without concrete methods may be a design problem and exists very rarely. But if that was the situation , whether we need to go with
    interface or abstract class? Please clarify.

    Thanks.

    DB:3.75:Abstract Class With Abstract Methods Only p7

    EJP wrote:
    Not really. I see the Java API has many ones that both have abstract and concrete methods.The second statement is irrelevant to the first statement. You have misunderstood what you are saying 'not really' to.Sorry, English is not my native language.

  • RELEVANCY SCORE 3.75

    DB:3.75: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:3.75: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 3.75

    DB:3.75:Abstract And An Interface ak


    Hi there,
    Can anybody please help me.I need to know the difference between the abstract and an Interface.Please explain me with a simple example.Thanks in advance.

    DB:3.75:Abstract And An Interface ak

    NJSun wrote:
    An abstract class is a class which may have the usual flavors of class members (private, protected, etc.), but has some abstract methods.Minor correction: An abstract class usually has abstract methods, but is not required to.

  • RELEVANCY SCORE 3.75

    DB:3.75:Re: A Small Doubt Regarding Abstract Classes... 7f



    HOWEVER, i was trying to figure out the possibility,
    /or the ramifications of
    allowing a class to EXTEND an
    interface,
    thereby, "inheriting" all the Contract...but since,
    we're NOT implementing...why NOT just mark the class
    as ABSTRACT..so that
    the first CONCRETE class down-the-family-tree...that
    extends this abstract class, will ALSO fulfill the
    CONTRACT which was ..."sort-of-signed by the
    ABSTRACT class....?!?"This is not what I would call an explicit contract fulfillment. By forwarding it to the next class, you basically don't enforce anything. You don't have this problem with inheritance, because inheritance always follows a tree structure, which forces every class in a very strong defined context.

    I have thought now for a couple of different scenarios. Technically, they would all work, although they get nasty here and there. I guess, in the end it's really a language decision to enforce interface fulfillment.

    DB:3.75:Re: A Small Doubt Regarding Abstract Classes... 7f

    Hi ppl..

    Why can't an Abstract class extend an
    Interface It can implement an interface, which is the same thing. Implements and extends both specify type inheritance in Java, and they're simply used in mutually exclusive cases. The rules of the language simply say to use one word for certain cases and the other word for the other cases. It could have just been on single word and everything would work the same way it does now. If an abstract class could extend an interface, it wouldn't mean anything different than implementing it.

  • RELEVANCY SCORE 3.75

    DB:3.75: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:3.75: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 3.75

    DB:3.75:Help With Interface And Abstract cs


    Hi all

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

  • RELEVANCY SCORE 3.75

    DB:3.75:Abstract Classes And Interfaces kp


    I am kinda new to Java but have been studying frequently. I have a question that is probably very simple: What is the difference/advantage between an abstract Class and an Interface?

    DB:3.75:Abstract Classes And Interfaces kp

    Search the forum. Here's a topic that addresses it:
    http://forum.java.sun.com/thread.jsp?forum=31thread=273324

  • RELEVANCY SCORE 3.75

    DB:3.75:Difference Between Abstract Interface And Normal Interface za


    Hello Friends,

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

    DB:3.75: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 3.72

    DB:3.72:Java Interfaces And Abstract Classed fc


    what is the difference between interface and abstract class?

    DB:3.72:Java Interfaces And Abstract Classed fc

    I suggest you try writing some code and see.

  • RELEVANCY SCORE 3.72

    DB:3.72:Java Programming 33


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

    DB:3.72: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 3.70

    DB:3.70:Use Of Abstract And Interface? k3


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

    DB:3.70: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 3.66

    DB:3.66: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:3.66: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 3.66

    DB:3.66:Confused Regarding Interface Mapping In Bpm Scenarion 8f



    hi

    my scenario goes like this:

    have 2 sources sendign files to target.

    Am using BPM to merge the input files into a single target file.

    am confused as to which interfaces to use in interface mapping.

    (have 3 abstract ,and 2 outbound and 1 inbound interfaces).

    am already using 2 abstract interfaces as input and 1 abstract target interface in o/p for nterface mapping.

    However ,while running the configuratin wizard,no interface mapping appears.

    please help me ASAP.

    DB:3.66:Confused Regarding Interface Mapping In Bpm Scenarion 8f


    Please close one of the open threads. There shouldn't be two threads with same question. This would confuse the posters.

    Regards,

    Prateek

  • RELEVANCY SCORE 3.66

    DB:3.66:Public Abstract Interface I{ d9


    Interface are totally abstract by default so what is the need of abstract in
    public abstract interface I{
    ........}does this have any functionality........

    DB:3.66:Public Abstract Interface I{ d9

    I believe it's entirely redundant.

    I believe that the "public" part is also entirely
    redundant.

    Check the language spec to be sure.Abstract is redundant--all interfaces and their methods are implicitly abstract.

    Public is redundant for interface methods--they're always public--but not for the interface itself. You can have package-scope interfaces. Not sure about private ones.

  • RELEVANCY SCORE 3.65

    DB:3.65:Interfaces And Abstract Classes 8x


    Whats the difference between an interface and an abstract class.

    DB:3.65: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 3.65

    DB:3.65: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:3.65:Abstract Class And Interface mc

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

  • RELEVANCY SCORE 3.64

    DB:3.64:Abstract Or Interface m8


    when to use abstract keyword and interface keyword.

    DB:3.64:Abstract Or Interface m8

    Don't just sit there mute with an open mouth and a stupid grin on your face expecting to be spoonfed replies you can copy into your homework. At least show a reaction for heavens sake! Anybody hoooooome?

  • RELEVANCY SCORE 3.62

    DB:3.62:Re: Why An Interface Is Used In A Java Program pc


    These are fair comments as per as interface is concern.... we need interface to declare the methods without implementing the methods. Basically interfaces help implementing classes in a organised way.
    Now We got abstract class also, which has got more or less same features like interfaces. In abstract class also we can declare a method without implementation.
    If we use abstract class and extend that abstract class, we don't have implement all the abstract methods in that particular class,which would extend the abstract class, but if we implement an interface in a class, we have to define all the methods with their body. Now, can anyone tell me , in a generic way, when do we use interface and when do we use abstract class. I don't need the differences between abstract class and interface...that i know...thanks in advance
    take it easy
    RD
    l

    DB:3.62:Re: Why An Interface Is Used In A Java Program pc

    For Ex: 5 years down the line, .........I always wondered why it is said "down the
    line" and not up the line.
    What's so downish about the future ?People degrade as the years pass by. :P

  • RELEVANCY SCORE 3.61

    DB:3.61: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:3.61:Abstract Classes Interface ? kd

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

    Kaj

  • RELEVANCY SCORE 3.61

    DB:3.61:Abstract Class Vs Interface 1x


    Hi I have a small doubt regarding this.
    When can i go for Abstract Class and When can i go for Interface.
    Anybody can help me?

    DB:3.61:Abstract Class Vs Interface 1x

    Hi I have a small doubt regarding this.
    When can i go for Abstract Class and When can i go for Interface.
    Anybody can help me?

  • RELEVANCY SCORE 3.58

    DB:3.58:Starnge Problem While Creating Container Elements In Bpm 71



    Hi All,

    I am trying to create Container element of category Abstract Interface in BPM. While I try to give Type as the abstract interface created, it not populating the my abstract interface and says: No obects found.

    Kindly, What could be the reason?

    Thx

    Navin

    DB:3.58:Starnge Problem While Creating Container Elements In Bpm 71


    Hi,

    You can use abstract sync inteface in the async-sync bridge (sender), using the async abstract interfaces as request and response to the sync abstract interface in the BPM sender properties configuration.

    Regards,

    Bill

  • RELEVANCY SCORE 3.56

    DB:3.56: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:3.56: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 3.54

    DB:3.54:What Is The Diff Between The Interface And Abstract 9x



    hi,

    could u plz explain the diff between the interface and abstract

    clearly.

    DB:3.54:What Is The Diff Between The Interface And Abstract 9x


    Hi Venkat,

    Check this link

    http://mindprod.com/jgloss/interfacevsabstract.html

    Thanks,

    Vinay

  • RELEVANCY SCORE 3.52

    DB:3.52:Interface 38


    Helo Sir,
    Iam sreedhar.L.
    I hope you will solve my doubt.
    This is my doubt...
    I have a abstract class ,i coded
    2 concrete methods(Implemented methods) and
    3 abstract methods.
    Now,
    why we have abstract class extra...
    just we can put the concrete methods in normal class and abstract methods in interface.
    why we need this extra abstract.
    please tell me
    thanks in advance

    DB:3.52:Interface 38

    This question, or one like it, has been asked many, many times. Try using google or this website's search function.

    The very short version: interfaces are used for defining a pure type, with no implementation. Abstract classes can do that, but are better suited for when you have a reasonable default implementation for some methods that you expect some subclasses to use.

  • RELEVANCY SCORE 3.50

    DB:3.50:Abstract Class And Interface 33


    When we have got is the interface then do you need is an abstract class? ....since i can divide an abstract class to two one is interface and the other a concrete class.....So where is the exact functionality of an abstract class.
    Why is that a file name should be the same as that of the public class declared in that file?

    DB:3.50:Abstract Class And Interface 33

    Why is that a file name should be the same as that of the public class declared in that file?Because that's what is required by the JVM.

  • RELEVANCY SCORE 3.50

    DB:3.50:Difference B/W Abstract Class And Interface mf


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

    Thanks in advance!

    DB:3.50: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 3.50

    DB:3.50:Interface And Abstract Class dd


    what is the difference between interface and Abstract class?
    What are the situations we have to go for interface and Abstract class?

    DB:3.50:Interface And Abstract Class dd

    Neither an abstract class nor an interface can be instantiated (meaning you cannot create the object directly with the "new" keyword). They are both similar in that they have abstract methods. (Technically, you can create an abstract class with no abstract methods, but I would question the utility of making that class abstract in the first place).

    The two main differences are the following:

    Implementation: An abstract class can implement methods, since it is a class. An interface can never implement any methods, it only declares their signatures.Inheritance: A given class can implement an unlimited number of interfaces. A class can only extend one class. In general, I use the following rules of thumb when deciding (other developers may have differing opinions):

    Given the choice, use an interface. Since you can implement an unlimited number of interfaces, they are not as restricted, from a class hierarchy perspective. If you have several classes with the same instance (class) variables declared and several methods that all accomlplish the same thing (normally, they will even have segments of code copy-pasted between classes), then re-factor the common variables and code into an abstract class. When using interfaces, always consider delegation. Delegation is something like the following:interface IFoo {
    abstract public void bar();
    }

    public class FooDelegate {
    final public void bar() {
    // Default implementation goes here
    }
    }

    public class FooImpl implements IFoo {

    final public void bar() {
    new FooDelegate().bar();
    }
    }

    The advantage of delegation is that you can write a "helper" that contains the implementation, and then the classes that actually implement the interface can simply use the helper (e.g., delegate the implementation to another class).

    - Saish

    "My karma ran over your dogma." - Anon

  • RELEVANCY SCORE 3.49

    DB:3.49: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:3.49: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 3.49

    DB:3.49:Abstact Class And Interface s9


    Hi,

    Any One Can Let me know the exact diff. Between the Abstract class and Interface.

    With
    BAbu

  • RELEVANCY SCORE 3.49

    DB:3.49:Abstract Class 9k



    i know the concept of abstract class in java and this concept is used in interface, i.e all the methods declared in interface are abstract. i want to know how the abtract class is different from the normal class in java

    DB:3.49:Abstract Class 9k

    all the answers you need can be found thru google: "java abstract class"

    http://java.sun.com/docs/books/tutorial/java/IandI/abstract.html

  • RELEVANCY SCORE 3.48

    DB:3.48:Abstract Class-Interface - Usage 71


    hai
    Give me details regarding the suituation of using
    1. Abstract class
    2. Interface

    DB:3.48:Abstract Class-Interface - Usage 71

    Basically an interface is a set of methods a class can promise to implement. An interface often expresses some aspect of a class that isn't related to the class hierarchy itself (that Dog, Duck and Cat extends Animal kind of stuff). It's often a common way to access stored objects like for example the Enumeration and Iterator interfaces.

    If a class has promised to implement an interface but doesn't, it becomes abstract. A class also becomes abstract if some methods are declared abstract. In both cases the class must be declared abstract and the actual implementation of the abstract methods is left over to subclasses.

    The reason for declaring a method abstract is one of design. The abstract class is often made to contain general information about something, and its subclasses are expected to fill in specific details by implementing the abstract methods. For example Animal can leave noise() abstract and let Dog, Duck and Cat provide the actual sounds.

  • RELEVANCY SCORE 3.48

    DB:3.48:Re: Inteface Vs Abstract Class dd


    interfaces are implented, abstract classes are extended. In an interface ther is no code or variables only methods and any class that implements the interface must provide code implementation for all the methods. An abstract class has code. Why you would use them i have no idea or i jsut fogot

    DB:3.48:Re: Inteface Vs Abstract Class dd

    Joshua Bloch has something to say about this... see the book "Effective Java" - one of the best Java books once you no longer consider yourself a beginner

  • RELEVANCY SCORE 3.47

    DB:3.47:Regarding Message Interface , Service Interface 7z



    Hi All

    My scenario is File to File from 1 application server to another application server ,without any transformation in PI 7.1 for service interface to be involved for Interface Pattern Stateless and Stateless (XI 3.0) compatible can only be used with Category Abstract

    only abstract catgory is possible , can'nt i make 1 outbound another inbound for this ?

    Regards

    Abhishek

    Edited by: Abhishek Agrahari on Feb 9, 2009 11:08 AM

    DB:3.47:Regarding Message Interface , Service Interface 7z


    Yes Rajesh

    you can can also learn ..there is a feature of of Integrate Configuration in PI 7.1 for the same , we can use for the same

    Thanks Patric for the valuable doc ,

    also the Blog is very useful /people/william.li/blog/2006/09/08/how-to-send-any-data-even-binary-through-xi-without-using-the-integration-repository

    Thanks !

    Abhishek

  • RELEVANCY SCORE 3.46

    DB:3.46: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:3.46: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 3.46

    DB:3.46:Regarding Abstract Interface sa


    Hello,What makes the difference between the Normal Interfaces and Abstract Interfaces. Is there any technical differences between these two interfaces.Thank you

    DB:3.46:Regarding Abstract Interface sa

    HIAbstract message interface donu2019t have a direction and arenu2019t implemented in an application system. We use them to define the process signature of an integration process.These are also called as hidden Interfaces.The Message interface is the highest level representation of XML meta data. It has two important attributes: mode (Synchronous or Asynchronous) and direction (inbound or outbound). For Business processes, Abstract interfaces are used; these have a mode, but no direction. oReferences fault message types for exception handlingoContext objects can be assigned.oWSDL representation available for exportoStarting point for Proxy generation (ABAP and Java).cheers

  • RELEVANCY SCORE 3.45

    DB:3.45:When We Go For Abstract ! 1c


    Hello friends,

    When we go for abstract class and when we go for interface?

    i think the interface are future use in realtime but abstract we must
    use immediatly?is it correct ?

    thanks and regards
    ramesh,

    DB:3.45:When We Go For Abstract ! 1c

    When we go for abstract class and when we go for
    interface?http://onesearch.sun.com/search/onesearch/index.jsp?qt=abstract+class+vs+interfacesubCat=site=devdftab=chooseCat=javaallcol=developer-forums

    317 results. _

    i think the interface are future use in realtime but
    abstract we must
    use immediatly?is it correct ?It has nothing to do with real-time and you are not correct.

  • RELEVANCY SCORE 3.45

    DB:3.45:Abstract And Interface fa


    Dear Sir/Madam,

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

    DB:3.45: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 3.45

    DB:3.45:Outbound And Abstract Sync Message Interface Difference zs



    Hi Experts,

    Is there any difference between the input and output messagetype for Outbound/Inbound Synch Message Interface and Abstract Sync Message Interface.

    Do we need to mention the same input and output messagetype for both outbound and Abstract or it should be otherway around?

    Regards

    Sara

    DB:3.45:Outbound And Abstract Sync Message Interface Difference zs


    ---Is there any difference between the input and output messagetype for Outbound/Inbound Synch Message Interface and Abstract Sync Message Interface.

    No there is not. U can select any message type irrespective of the type of message interface.

    ---Do we need to mention the same input and output messagetype for both outbound and Abstract or it should be otherway around?

    Yes. As per ur requirement u can specify the same.

    Regards,

    Prateek

  • RELEVANCY SCORE 3.45

    DB:3.45: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:3.45: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 3.45

    DB:3.45:Difference Between Abstract Class And Interface ? fz


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

    DB:3.45: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 3.45

    DB:3.45:Regarding Dynamic Binding And Abstract Class pp


    Hello Java Community,

    In dynamic biniding consept, it binds the appropriate method at run time... can any one please give me the reason how it identifes that perticular method is nearst one.....( i know that it first check sub class and then goes to super class ....... i just want how it identifys this process).....

    As per java soft new release JDK1.5 we can also write abstract class with out implimenting methods(even partially also) ... in this case if i declare all methods in abstract class were "public abstract " (like in interface methods return type) it will be similar as interface ......... and i just want in this case what is the difference between interface and abstrace class

    DB:3.45:Regarding Dynamic Binding And Abstract Class pp

    hello Sumit.Tyagi

    Thanks Q for responding...... and thanks for clearing my doubt....

    Regards
    sricharan

  • RELEVANCY SCORE 3.45

    DB:3.45:About Abstract Interface And It's Method pj


    Hi !!

    HttpSession session = request.getSession();

    getSession() is the Method of HttpSession and it is the abstract interface..
    right ??

    so how can we call the abstract method and ..

    here... request is the object of HttpServletRequest which is abstract interface so how can we make an Object of this abstract interface...

    I m very confused Please solve my Querry ASAP

    DB:3.45:About Abstract Interface And It's Method pj

    As far as I can tell, these three threads are all the same person asking the same question.

    http://forum.java.sun.com/thread.jspa?threadID=5188609
    http://forum.java.sun.com/thread.jspa?threadID=5188638
    http://forum.java.sun.com/thread.jspa?threadID=5188603

    How obnoxious.

  • RELEVANCY SCORE 3.44

    DB:3.44:Re: Is It A Issue With The War Structure mz


    Hi,
    Please check with the iASAT and click on the application button check if your application under "module". In your case please refer to fortune application, that way, you can help yourself by learning if you have packaged your application in a right way.
    Next, I havent' tested this but, I believe getLocale() is not a part of HttpServletRequest because of the following reason...

    C:\javap javax.servlet.http.HttpServletRequest
    Compiled from HttpServletRequest.java
    public interface javax.servlet.http.HttpServletRequest extends javax.servlet.ServletRequest
    /* ACC_SUPER bit NOT set */
    {
    public abstract javax.servlet.http.Cookie getCookies()[];
    public abstract java.lang.String getMethod();
    public abstract java.lang.String getRequestURI();
    public abstract java.lang.String getServletPath();
    public abstract java.lang.String getPathInfo();
    public abstract java.lang.String getPathTranslated();
    public abstract java.lang.String getQueryString();
    public abstract java.lang.String getRemoteUser();
    public abstract java.lang.String getAuthType();
    public abstract java.lang.String getHeader(java.lang.String);
    public abstract int getIntHeader(java.lang.String);
    public abstract long getDateHeader(java.lang.String);
    public abstract java.util.Enumeration getHeaderNames();
    public abstract javax.servlet.http.HttpSession getSession(boolean);
    public abstract java.lang.String getRequestedSessionId();
    public abstract boolean isRequestedSessionIdValid();
    public abstract boolean isRequestedSessionIdFromCookie();
    public abstract boolean isRequestedSessionIdFromUrl();
    }

    Subsequently, I found that getLocale() method is associated with HttpRequest. Please visit the following URL and let me know your opinion on this.

    http://xml.apache.org/cocoon/apidocs/ org/apache/cocoon/environment/http/ HttpRequest.html

    Regards
    Raj

    DB:3.44:Re: Is It A Issue With The War Structure mz

    Hi All,

    I have deployed 2 ear's with some jar's and a war file

    the first ear file contains war1 which has the following directory structure

    war1 --

    root\
    Login.jsp
    WEB-INF
    classes
    lan.properties
    test
    modules
    html
    Hello.jsp

    URL1 http://localhost/NASApp/test/Login.jsp

    the Login.jsp file redirects to the file Hello.jsp

    the second ear file contains war2 which has the following directory structure

    war2 --

    WEB-INF
    classes
    lan.properties
    Hello.jsp

    URL2 http://localhost/NASApp/test2/Hello.jsp

    Hello.jsp file access the properties file with in the WEB-INF\classes directory

    The problem is the URL2 loads fine, where as the URL1 throws the following error

    javac error: d:\iplanet\ias6\ias\APPS\test\testweb\WEB-INF\compiled_jsp\jsp\APPS\testweb\test\modules\html\Hello.java:86: Method getLocale() not found in interface javax.servlet.http.HttpServletRequest. Locale locale1 =request.getLocale(); ^ 1 error

    how come this happens both URL's loads and access the same file only the war structure is different..
    could anyone help me out to rectify this issue?

    tks in advance
    meera

  • RELEVANCY SCORE 3.44

    DB:3.44:What Is The Different Between Abstract An Interface Class? jf


    what is the different between abstract an interface class?
    and
    What is the different between access specifier of public and friendly.

    DB:3.44:What Is The Different Between Abstract An Interface Class? jf

    what is the different between abstract an interface
    class?interfaces contain only signatures of method you'll have to implement and constant
    whereas abstract classes contains method implemented and/or method non implemented

    What is the different between access specifier of
    public and friendly.the scope of 'friendly' is the package which contains it

  • RELEVANCY SCORE 3.44

    DB:3.44: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 3.44

    DB:3.44: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:3.44:Abstract Class And Interface???? ja

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

  • RELEVANCY SCORE 3.44

    DB:3.44:Abstract Class And Interface z1


    What is most important thing about abstract class and interface.

    When to use abstract class and interface.

    DB:3.44: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 3.43

    DB:3.43: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:3.43: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 3.43

    DB:3.43:Confused Regarding Interface Mapping In Bpm Scenarion 3p



    hi

    my scenario goes like this:

    have 2 sources sendign files to target.

    Am using BPM to merge the input files into a single target file.

    am confused as to which interfaces to use in interface mapping.

    (have 3 abstract ,and 2 outbound and 1 inbound interfaces).

    am already using 2 abstract interfaces as input and 1 abstract target interface in o/p for nterface mapping.

    However ,while running the configuratin wizard,no interface mapping appears.

    please help me ASAP.

    DB:3.43:Confused Regarding Interface Mapping In Bpm Scenarion 3p


    Hi...

    Whenever you use transformation in BPM process where you will mention interface mapping there itself, so you cant see the it in interface determination. Your scenario is configured correctly.

    Regards

    Leela

  • RELEVANCY SCORE 3.43

    DB:3.43:Abstract Class And Interface 97


    is it any differences between abstract class and interface?

    DB:3.43: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 3.42

    DB:3.42:Abstract Class Interface jx


     
     Hi,
     
      In C# is it allowed for an Abstract class to inherit from an interface and then not implement that interface. This is to force the classes that derive from the abstract class  to provide implementation for the interface(s) as well.
     
    thanks
     

    DB:3.42:Abstract Class Interface jx

     
     Thanks Hans,
     
     I have now understood the semantics (I hope I am right) . I think it would have been more appropriate if we did not need to write the extra abstract function. The class inherits
    from an interface and since its abstract anything missing should be provided by the child class.
     
    that does answer my question though, do you think I make sense here
     

  • RELEVANCY SCORE 3.42

    DB:3.42:Abstract Class Inheriting Another Abstract Class ck


    If I have an "Abstract" class that has the following methods:

    Abstract A
    getX();
    abstract getY();
    abstract getXY();And, another "Abstract" class that "INHERITS" A:

    Abstract B extends AWill the "Abstract" methods in class A be ALSO "Abstract" in class B?

    Thanks.

    DB:3.42:Abstract Class Inheriting Another Abstract Class ck

    Think about it: the alternative would be they are no longer abstract methods -- so where did their mystery bodies come from?

  • RELEVANCY SCORE 3.42

    DB:3.42:Interface Vs Abstract Class d8


    when do we need interface and when abstract class?

    DB:3.42: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 3.42

    DB:3.42:Query Regarding List Interface And Implementation. md


    interface List{
    int size();
    boolean isEmpty();
    }

    abstract class AbstractList implements List{

    public int size();

    public boolean isEmpty(){

    return size() == 0;

    }

    }

    public class ArrayList extends AbstractList(){

    public int size() {
    return 0; // placeholder.
    }
    }Query :

    How can the abstract class AbstractList invoke size() == 0
    in isEmpty(), when there is no size() implemented at all?

    In ArrayList class, what is the meaning of the placeholder?

    If I create an instance of ArrayList and invoke the size(),
    wont I always be returned value of 0?

    DB:3.42:Query Regarding List Interface And Implementation. md

    I don't quite get this. These are not snippets from the sources of java.util.List, java.util.AbstractList and java.util.ArrayList.

    As to your question regarding how AbstractList's isEmpty method can invoke size(), AbstractList is abstract. As such it can not be instantiated, so when calling isEmpty, it will always invoke size() of some concrete extension of AbstractList. A concrete class can not have abstract methods and thus must provide an implementation of size().

  • RELEVANCY SCORE 3.42

    DB:3.42:Interfaces And Abstract Classes fk


    hi,

    Can anyone help me regarding the difference between interfaces and abstract classes. What is the advantage of interface over abstract classes and viceversa. Obout the possibities of multple inheritance I know. I found allmost all people are talking some external answers.
    Why an abstract class cant we do it with concrete class.
    regards,

    Jayaprasad Viswanathan

    DB:3.42:Interfaces And Abstract Classes fk

    Abstarct class can never be instantiated. Same as interfaces.

    Can be
    subclassed.Same as interfaces.

  • RELEVANCY SCORE 3.42

    DB:3.42: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:3.42:Interface And Abstract Class ac

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

  • RELEVANCY SCORE 3.41

    DB:3.41:Re: Which One Is The Best And Why cs


    But implementing interface is generally more
    difficult than extending (abstract) class, because
    (abstract) class provides more things than
    interface.For a start that is wrong, it depends on the interface/abstract class.

    Secondly implementing is not relivent at all to this.

    DB:3.41:Re: Which One Is The Best And Why cs

    I think when ,
    A obja = new B();
    is used the instance variable and methods will
    not be accessible evia obja.Correct.

    B obja = new B();
    is used the instance variable and methods can
    be accessed via obja , which may involve bit more
    memory usage than the previous case .So its betterUtter BS, sorry. The object still is an instance of B.

    to go for the last case if v dont need B instance
    members not to be accessed.That doesn exist.

    and also if A is implemented by many classes
    in the ejb for bussiness logic purpose , only the
    interface is sent back as return value hiding the
    concrete class (Encapsulation)That is generalization or abstraction, not encapsulation.

    .obviously cannot have
    the concrete class with definition in the calling
    end.Huh?

  • RELEVANCY SCORE 3.40

    DB:3.40: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:3.40: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 3.40

    DB:3.40: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:3.40: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 3.39

    DB:3.39:Interface And Its Methods dm


    Hi !!

    HttpSession session = request.getSession();

    getSession() is the Method of HttpSession and it is the abstract interface..
    right ??

    so how can we call the abstract method and ..

    here... request is the object of HttpServletRequest which is abstract interface so how can we make an Object of this abstract interface...

    I m very confused Please solve my Querry ASAP

    DB:3.39:Interface And Its Methods dm

    As far as I can tell, these three threads are all the same person asking the same question.

    http://forum.java.sun.com/thread.jspa?threadID=5188609
    http://forum.java.sun.com/thread.jspa?threadID=5188638
    http://forum.java.sun.com/thread.jspa?threadID=5188603

    How obnoxious.

  • RELEVANCY SCORE 3.38

    DB:3.38:Local Interface Inherited By Extending Abstract Class: Canno 8k



    Hello,I just stumbled upon a strange behaviour regarding a stateless session bean. I'm using Jboss 4.0.5 GA, JDK 5.0 and have an enterprise application with a Stateless Session Bean structered like this:
    @Local
    interface Logic {
    void foo();
    }

    abstract class AbstractLogic implements Logic {
    void foo() {
    bar();
    }

    abstract void bar();
    }

    @Stateless
    class LogicBean extends AbstractLogic {
    void bar();
    }

    DB:3.38:Local Interface Inherited By Extending Abstract Class: Canno 8k


    The same issue exists in Jboss 7.1.1 release also. It was working 5.1 releases.

    Khem

  • RELEVANCY SCORE 3.38

    DB:3.38:Interface V/S Abstract Interface 3x


    I am bit confused in one place during the declaration of Interface. as you know I can define a Inteface in two way,

    a) public interface InterfaceTest {

    public void test();

    } b) public abstract interface InterfaceTest {

    public abstract void test();

    }In first case I declare a normal Interface and in second case done with a abstract keyword. Both are working in a same manner.

    But when Java allow us to declare it in two ways, the their must be a reason behind the scene.

    Can you explain me the reason behind this tow type of Interface declaration

  • RELEVANCY SCORE 3.38

    DB:3.38:What Is The Difference Between Abstract Class And Interface jf


    Hi,
    Can you please tell me the differences between Abstract class and Interface.
    In which scenarios we have to use Abstract class and in which scenarios should use Interface.

    Thanks and Regards
    Kranthi

    DB:3.38:What Is The Difference Between Abstract Class And Interface jf

    http://stackoverflow.com/questions/761194/interface-vs-abstract-class-general-oo

  • RELEVANCY SCORE 3.38

    DB:3.38: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:3.38:Abstract Class Vs Interface 9a

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

  • RELEVANCY SCORE 3.38

    DB:3.38:Re: Interface And Abstract pm


    An interface should be used to define a protocolfor
    usage of all implementing classes where as an
    Abstract class should be used when some of the
    functionality is clearly defined but some on the
    other hand is well "abstract"Indeed. Often enough, I use both an interface and
    an abstract class.Likewise.

    I don't know that I've ever "chosen between" an interface and an abstract class. To me they serve completely different roles, often working together. It's like choosing between toast and milk--they're not even both candidates for the same job.

    DB:3.38:Re: Interface And Abstract pm

    ..[if you] want to add a whole set of functionalities
    which are going to affect a greater chunk of your code,
    then it can, and should be, achieved using an interface
    which can then be implemented into the respective
    classes with minimum code alteration.Minimum code alteration? Wouldn't you have to add "implements NewInterface" after each class name, and then in each class implement all the methods in the interface? It doesn't appear that an interface achieves "minimum code alteration." Couldn't you forgo using an interface and just implement the methods in each class? That would save you from having to write "implements NewInterface" after each class name? Therefore, there would be less code alteration by not using an interface.

    This functionality can't be achieved using
    an abstract class.Why not? You could implement all the interface methods in the base classes, and they would be inherited automatically by all the subclasses--with the result being much less code alteration.

    It doesn't sound like code alteration can be used as the basis for deciding between using an interface or an abstract class.

    arunts,

    I've never read a satisfactory explanation of the differences between interfaces and abstract classes, and the subject crops up here regularly.

  • RELEVANCY SCORE 3.37

    DB:3.37:Regarding Abstract Interface mz


    Hello Experts, I am new to BPM concepts, How can we know about how many abstract interfaces we have to develop for a scenario.Based on which conditions we have to take decisions to develop the Abstract Interfaces.Thank you in advance

    DB:3.37:Regarding Abstract Interface mz

    Hi,What is Abstract InterfaceAbstract interface can does not have a direction. Its direction is determined during the runtime. This type is basically used in Integration Process (BPM) where an interface can be used to both send and receive messages.During the runtime, its direction is determined whether to send or receive.how many abstract interfaces we have to develop for a scenarioDepends on the scenario, requirement. But at least one Abstract Interface is required to receive the message in BPM.Just go through these links you will understandBPM in XIhttps://www.sdn.sap.com/irj/sdn/wiki?path=/display/xi/integrationProcess%28ccBPM%29inXIBPM-1Walkthrough with BPMBPM-2Reconciliation of Messages in BPMBPM-3RFC Scenario using BPM --Starter KitBPM-4The specified item was not found.Schedule BPMSchedule Your BPMUse of Synch - Asynch bridge in ccBPMDemonstrating Use of Synchronous-Asynchronous Bridge to Integrate Synchronous and Asynchronous systems using ccBPM in SAP Xi Use of Synch - Asynch bridge in ccBPMhttps://www.sdn.sap.com/irj/sdn/weblogs?blog=/pub/wlg/1403 [original link is broken] [original link is broken] [original link is broken]without BPMSync/Async scenarios without BPMwithout BPM1Sync/Async communication in JMS adapter without BPM (SP19)IDOC BPMIDOCs (Multiple Types) Collection in BPMmultimapping without BPM/people/jin.shin/blog/2006/02/07/multi-mapping-without-bpm--yes-it146s-possibleThanksVikranth

  • RELEVANCY SCORE 3.36

    DB:3.36:Question On Interface. f8


    What is the difference between the following declarations
    "public abstract interface" and "public interface "
    For example consider the following statements
    public abstract interface Test{

    void check();
    }

    public interface Test{

    void check();
    }

    Could any one help me.
    Thanks

    DB:3.36:Question On Interface. f8

    Actually, exactly the opposite is true. There are no concrete interfaces, only abstract ones. It's just that you normally don't put the abstract keyword in the source code because it's implicit.

  • RELEVANCY SCORE 3.36

    DB:3.36: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 3.35

    DB:3.35:Abstract Interface zd


    What is abstract interface? why it is called so? what is the use of this interface?

    DB:3.35:Abstract Interface zd

    What is abstract interface? why it is called so? what
    is the use of this interface?An abstract interface is the same as a normal interface. The word abstract has no implications here.

    Sources:
    http://www.jguru.com/faq/view.jsp?EID=280487

  • RELEVANCY SCORE 3.34

    DB:3.34: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:3.34: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 3.34

    DB:3.34:What Is The Exact Difference Between Abstract Classes And Interface 7m


    What is the exact difference between abstract classes and interface in real scenario???

    Plz could you give a practical example???

    Thanks

    DB:3.34:What Is The Exact Difference Between Abstract Classes And Interface 7m

    At least your head doesn't make a plonk sound.Mine just makes a splutchy bursting watermelon type sound.

    To the original poster - to make things simple, if there is any doubt about which you should use, use an interface. If the situation calls for an abstract class, you will know that an interface is the wrong choice, because it will be impossible to do what you want to do with an interface.

    Drake

  • RELEVANCY SCORE 3.34

    DB:3.34:When To Use Abstract Class And Interface? jp


    hi,

    When to use Abstract class and Interface?

    DB:3.34: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 3.34

    DB:3.34:Difference ???? xz


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

    DB:3.34: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 3.33

    DB:3.33: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 3.33

    DB:3.33: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:3.33: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 3.33

    DB:3.33: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:3.33: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 3.33

    DB:3.33:Abstract? Interface? dm


    Hello! Can anybody explain me the difference between abstract classes and interface? when should i use them? Can you please give me examples?

    Thank you in advance!

    DB:3.33:Abstract? Interface? dm

    *** Abstract:

    Abstract classes are classes which are not designed to be used by the programmer. They simply enforce the declaration of certain methods on any class which subclasses them. Abstract classes can contain method declarations and instance variables.

    An example would be a very simple driving game, which offers a choice of different cars. Each car moves in the same manner, acceleration, etc. The only difference is the graphic which is used to display each car on screen. For this implementation, it would make sense to have an abstract class 'Car' which defines all the methods such as getSpeed, getDirection, setSpeed, setDirection, and so on. Its one abstract method would be getGraphic. The Car class cannot define this method since it models the 'general case' car, and so does not know what graphic is appropriate for each car.

    abstract class Car {

    /**
    * Define all the methods which are appropriate for each Car object
    */
    public int getSpeed() {
    return speed;
    }

    public void setSpeed(int i) {
    speed=i;
    }

    //etc

    //declare the abstract method
    public abstract Icon getGraphic();
    }Now you could subclass the Car class for a particular Car object:
    public class Mini extends Car {
    public Icon getGraphic() {
    return new ImageIcon("Mini.gif");
    }
    }To summarise, abstract classes are useful if you have a set of similar objects which have most of the same properties, but some method(s) are only appropriate for each individual object.

    *** Interface:

    Interfaces are useful when you need to disguise your object(s) as another type of object. By implementing the interface, the VM can recognise this.

    Interfaces differ from abstract classes in that you must write all the functions yourself. They provide no properties or methods in the base class, whereas abstract classes do.

    I hope this helps, but you would probably be best to scour the java tutorial for this topic for better examples.

  • RELEVANCY SCORE 3.33

    DB:3.33:When To Use Abstract Class And Interface 3z


    What is the scenario to use abstract class and interface

    DB:3.33:When To Use Abstract Class And Interface 3z

    Read this too, if you have time. :)
    http://java.sun.com/developer/JDCTechTips/2001/tt1106.html#tip2

  • RELEVANCY SCORE 3.33

    DB:3.33:Interface And Abstract Class c3


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

    DB:3.33:Interface And Abstract Class c3

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

    Double your pleasure or not!

  • RELEVANCY SCORE 3.32

    DB:3.32:Difference Between Interface And Abstract Interface 9j


    Hi Guy's,

    Any one Can Help me why the servlet 2.3 introduce the abstract interface.Is there any particular reason.

    bez,I didn't find any abstract interface in servlet 2.2.

    with
    babu

    DB:3.32:Difference Between Interface And Abstract Interface 9j

    I'm agreeing with ur point but I'd like to know why they have Mentioned abstract interface in servlet 2.3 Spec.Is there any reason.

    with
    Babu

  • RELEVANCY SCORE 3.32

    DB:3.32:Make Abstract Class With Interface. 39


    I want to make an abstract class with methods that need interfacing, but I don't want to make an entire other class for the abstract class to implement. Is there any way to make an abstract class and interface combined into one class with no implementations on that class?

    DB:3.32:Make Abstract Class With Interface. 39

    if you want a class with no implementations that what you need is an Interface

  • RELEVANCY SCORE 3.32

    DB:3.32:Abstract Calss Vs Interface af


    hi all,

    what are the pros and cons of abstract calss and interface?
    when to use abstract class and when to use interface???

    thanks.

    DB:3.32:Abstract Calss Vs Interface af

    Well.. this is very basic question and asked many times. Googling this question may give you good results...

  • RELEVANCY SCORE 3.32

    DB:3.32:Abstract And Interface? cm


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

    DB:3.32:Abstract And Interface? cm

    Oh please, do some research of your own.

  • RELEVANCY SCORE 3.31

    DB:3.31:Copy Value Of Container (Abstract Interface) To An Other Container cm



    Hello,

    Is it possible to copy the value of an container (abstract interface) in BPM to an other container (abstract interface)?

    Thanks and regards

    Verena

    DB:3.31:Copy Value Of Container (Abstract Interface) To An Other Container cm


    Hi Verena,

    If you have the entire msg that you want to want in a container then you can probably use APPEND in container operation.

    But if your msg is a part of an intermediate strucure like the one i showed in my previous posts, then you Have to use Mapping in a BPM Transformation step for the simple reason that you cannot change a message by using a container operation.

    Regards,

    Sridhar

  • RELEVANCY SCORE 3.31

    DB:3.31:About Interface In Java 7z


    what is basic idea behind the interface and abstract class

    DB:3.31:About Interface In Java 7z

    Search in this forum. You will find lot of threads discussing the same topic.