• RELEVANCY SCORE 5.39

    DB:5.39: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:5.39:Difference Between Pure Abstract Class And Interface? 89

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

  • RELEVANCY SCORE 5.14

    DB:5.14:Abstract Class 13




    Difference between abstract class and interface
    use of abstract class

    DB:5.14:Abstract Class 13

    This question has been asked here about a billion times:

    http://search.java.sun.com/search/java/index.jsp?qt=interfacenh=10qp=st=11rf=0since=country=language=charset=variant=col=javaforums

  • RELEVANCY SCORE 4.40

    DB:4.40: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:4.40: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 4.40

    DB:4.40: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:4.40: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 4.37

    DB:4.37:Public Abstract Interface Filterconfig pf


    public abstract interface FilterConfig

    what is this class actually . is it abstract class or interface?

    DB:4.37:Public Abstract Interface Filterconfig pf

    interfaces are abstract because you cannot
    instantiate them.

    like you cant instantiate a abstract class.It's the other way around. You cannot instantiate them because they're abstract. Only what's fully concrete can be instantiated.

  • RELEVANCY SCORE 4.28

    DB:4.28:Diffrence Between A Interface And A Abstract Class? f7



    Hi OO ABAP Gurus

    Please clear below point to me.

    Diffrence between a Interface and a abstract class?

    Many thanks

    Sandeep Sharma..

    DB:4.28:Diffrence Between A Interface And A Abstract Class? f7


    Interface:

    All the methods of the class ARE UNDEFINED. You need to implement the interface in a class and give the method definition now. In other words INTERFACES just have the declarations no definitions.

    Abstract Class:

    All the methods which are defined for the class may have the definition or may not. Say we have 3 methods defined for this particular abstract class but only 2 have the definition and 1 does not have the definition. Then it becomes the abstract class.

    So, every Interface is a abstract class but not every abstract class is interface.

  • RELEVANCY SCORE 4.28

    DB:4.28:C#.Net Difference Between Abstract Class And Sealed Class df


    Hi Experts, What is Difference Between Abstract Class And Sealed Class in C#? Thanks.

    Knowledge Shared Is Knowledge Gained

    DB:4.28:C#.Net Difference Between Abstract Class And Sealed Class df

    Hi Geert van Horrik, Thanks.Knowledge Shared Is Knowledge Gained

  • RELEVANCY SCORE 4.28

    DB:4.28: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:4.28: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 4.28

    DB:4.28: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:4.28: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 4.23

    DB:4.23: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:4.23: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 4.15

    DB:4.15:Difference Between Abstract Class And An Interface c3


    hi all,

    what is the difference between an ABSTRACT CLASS with full of METHOD DEFINITIONS and no implemented methods. AND an interface having the same definitions.

    In which situation we use abstract class and in which situation we use interface.

    what are the benefits.

    Can anybody explain it clearly.

    bye
    -hari

    DB:4.15:Difference Between Abstract Class And An Interface c3

    http://www.google.com/search?q=java+difference+abstract+interfaceTrying to teach a man to fish, are you?

  • RELEVANCY SCORE 4.15

    DB:4.15: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:4.15: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 4.15

    DB:4.15:Re: What Is The Difference Between An Interface And An Abstract Class? 1a


    8000 views already wow.

    DB:4.15: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 4.15

    DB:4.15: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:4.15: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 4.15

    DB:4.15:What Is The Difference Between....... zf


    Hi, all,

    I am new to this java technology.

    I want to know, what are the differences between

    1) Interface and Abstract classes

    2) Implementing and extending a class

    Please help
    Regards
    Ash

    DB:4.15:What Is The Difference Between....... zf

    Hi,

    I am not an expert on Java, but what I know is that if a class is declared as an interface then it means it only provides a set of methods that have no implementations. So another class will implement that interface class by providing implementations to all those methods that are defined in the interface class. And a class can implement many interfaces. On the other hand if a class is declared as an abstract class then it provides methods that may or may not have implementation and another class will extend this abstract class and can override either all or some methods based on its needs. And a class can extend only one class at a time!

    I hope if my explanation is wrong, someone will correct me.

  • RELEVANCY SCORE 4.11

    DB:4.11:What Is The Main Difference Between Interface And Abstract Class 37


    Hi ,

    Please help on this ..

    Regards,
    vij

    DB:4.11:What Is The Main Difference Between Interface And Abstract Class 37

    All the methods declared inside interface should be abstract

    All the methods declared for an interface are abstract, by definition.

    but in case of abstract class at least one method should be abstract

    No. An abstract class is not required to have any abstract methods. It's not even a "should".

    Abstract class must be extended abstract ()
    methods generally contain only declaration part
    without definition part.
    No "generally" about it, as there are no exceptions. Abstract methods do not have a declared body, by definition.

    ~

  • RELEVANCY SCORE 4.10

    DB:4.10:Re: Difference Between Abstract Class And Interface. f3


    Thanks, jverd. I have got it.

    George

  • RELEVANCY SCORE 4.06

    DB:4.06:Re: Difference Between Abstract Class And Interface 7k


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

    DB:4.06: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 4.05

    DB:4.05: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:4.05:Differance Between Abstract Class And Interface 7s

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

  • RELEVANCY SCORE 3.99

    DB:3.99:Diff Between Abstract Class And Interface - Is This A Difference 7m


    This is quite a common topic thats discussed in any java forums . I would like to confirm if asked about the differences , can I say the following?.

    Abstract class can (or not ) have methods in it and it has no use in instantiating it since it has no meaning in instantiation.
    It has to be inherited for use .
    You need to INHERIT to use an abstract class.
    You can have a variable in Abstract class. ( a silly difference )
    Basically u use an abstract class when you want to provide a generalized form of abstraction and leave the implementation task with the inheriting subclass.

    Interface - group of related methods with empty bodies .
    You need to IMPLEMENT to use an interface.
    I dont think you can have a variable in a interface.
    When you want a few classes to use a few methods which you dont want to be included in the class ,then you go for the interface, which makes it easy to just implement and make use of the methods defined in the interface. But the problem with the interface is that, u have to implement all the methods defined in the interface , even if you dont need some of them.

    PLEASE LET ME KNOW IF THE VARIABLE THING IS A REAL DIFFERENCE. .
    I CANNOT HAVE A VARIABLE DECLARED IN MY INTERFACE RIGHT?

  • RELEVANCY SCORE 3.96

    DB:3.96:Difference Between Abstract Classes And Interfaces And When To Use Each a1


    Hi,
    I want to know the exact implementation differences between an abstract classes and Interfaces.
    When would we use each of them..
    Its seems that each does the same kind of functionality...but we need to just extend an abstract class in one and implement an Interface in another.

    Do let me know.

    Thanks,
    Ravi

    DB:3.96:Difference Between Abstract Classes And Interfaces And When To Use Each a1

    Hi,
    I want to know the exact implementation differences
    between an abstract classes and Interfaces.
    When would we use each of them..
    Its seems that each does the same kind of
    functionality...but we need to just extend an abstract
    class in one and implement an Interface in another.

    Do let me know.

    Thanks,
    RaviHi Ravi,
    A class must be declared abstract if one or more of its method is abstract. In case of an Interface, ALL the methods MUST be abstract. As java does not support multiple inheritence, Interface comes handy. In java, a class cannot extend from more than one class. To incorporate multiple inheritance, one can extend a class from another class and implement interface.

    public TestClass extends AbsClass implements Inter {
    }

    Thanks,
    Hope this helps,
    Karthick

  • RELEVANCY SCORE 3.96

    DB:3.96:Diff Interface And Abstract Class af


    I would like to know difference between Interface and abstract class.

    I know simple differences ... like with iterface u can achieve multiple inheritence and with abstract class can have method definition.

    It is said that with interface u achive less coupling, while its other way with abstract class.

    What exactly does this mean ?? how this is implemented programatically ??

    Cheers,
    Rana

    DB:3.96:Diff Interface And Abstract Class af

    You're not saying this is a reason not to use interfaces, are
    you?I haven't (yet) had this situation happen to me as a result of evolution of my APIs but I would think that's one thing to consider when choosing whether you should go with an abstract class or an interface for a supertype.

  • RELEVANCY SCORE 3.96

    DB:3.96:Difference Between Abstract Class And Interface j3


    What is the difference between anabstract class and aninterface ?

    DB:3.96:Difference Between Abstract Class And Interface j3

    Hi,
    Check this link differencebetween an abstract class and an interfacePS.Shakeer Hussain

  • RELEVANCY SCORE 3.94

    DB:3.94:Difference Between Abstract Class And Interfaces 9a


    Hi,

    Any body can tell me In which scenarios we use abstract class and in which scenario we use interfaces.

    In real time applications.

    DB:3.94:Difference Between Abstract Class And Interfaces 9a

    [url http://www.javaworld.com/javaworld/jw-09-2001/jw-0921-interface.html] maximizing flexibility

  • RELEVANCY SCORE 3.94

    DB:3.94: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:3.94: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 3.92

    DB:3.92:Difference B/W Abstract Class And Interface mf


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

    Thanks in advance!

    DB:3.92: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 3.91

    DB:3.91: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:3.91: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 3.85

    DB:3.85: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 3.81

    DB:3.81: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:3.81: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 3.80

    DB:3.80:Difference Between Abstract Interface And Normal Interface za


    Hello Friends,

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

    DB:3.80: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 3.78

    DB:3.78:Core Java 83


    what is differernce between abstract class and interface?

    DB:3.78:Core Java 83

    jwenting wrote:
    maybe an attempt at counting only posts which make any kind of sense at all?Where did the '1' come from then?

  • RELEVANCY SCORE 3.78

    DB:3.78:Java Interfaces And Abstract Classed fc


    what is the difference between interface and abstract class?

    DB:3.78:Java Interfaces And Abstract Classed fc

    I suggest you try writing some code and see.

  • RELEVANCY SCORE 3.76

    DB:3.76:Abstract Class 71


    Hi,
    can u tell me the exact difference between abstract class and interface.under which situations we should use this.

    DB:3.76:Abstract Class 71

    AmitChalwade123456 wrote:
    Anumanick wrote:
    Hi,
    can u tell me the exact difference between abstract class and interface.under which situations we should use this.A class implementing an interface must implement all of the methods defined in the interfacepublic abstract class ImNotImplementingThat implements Runnable {

    // public void run() {} I was going to implement this, but I can't be bothered

    }while a class extending an abstract class need not implement any of the methods defined in the abstract class. public class WhyAreYouMoaningAboutRead extends java.io.InputStream {

    // I won't compile, because I'm not implementing the abstract void method 'read'

    }Additionally, a class extending an abstract class can implement an infinite number of it's own methods.Erm

    An abstract class can contain non-abstract methods which do not have to be overridden in the subclass.Indeed

  • RELEVANCY SCORE 3.72

    DB:3.72:Difference Between The Interface And Abstarct Class ss


    HI all,I have a doubt over Difference between the Interface and Abstarct classi.e interface came into play for these reasons1. pure abstartc class (this can be done using abstartc class tooo)2. multiple inheritanceif i declare a abstartc class with only abstract methods does that ressembles interface i mean them interface adn abstartc class are same ? (except inheritance case)or is any difference in case of memmory allocation etc.,Regards

    Manoj Mathe

    DB:3.72:Difference Between The Interface And Abstarct Class ss

    In interface, you can only have Public access modifier.In abstract class, all acces modifiers are allowed.For example, if you need to declare abstract methods that are internal, private, etc... and that there is no multi inheritance,you need an abstract class.There are other differences.Check this :http://www.codeproject.com/KB/cs/abstractsvsinterfaces.aspxIn terms of memory allocation, I would say it's the same, both are Reference Types, and are so managed in the same way.Hope this helps,Tom

    Thomas Aimonetti - C# - Sharplog Engineering

  • RELEVANCY SCORE 3.70

    DB:3.70:Diff. Between Interface And Abstract Class 8j


    hi,
    Can any one tell me about diff between interface and abstract class in practical way.advanced thanks for ur response.
    -PVMVS

    DB:3.70:Diff. Between Interface And Abstract Class 8j

    An interface is a way to specify a set of abstract methods that you want a class to implement. The big deal is that the compiler will check that the methods are in fact provided by the class.

    Interfaces almost always represent a view that has nothing to do with the class hierarchy. It could for example be a specific way to access data, like an iterator. Iterators have seldom anything to do with the logical class design. It's just a common way to iterate through the elements of any class.

  • RELEVANCY SCORE 3.68

    DB:3.68:Interfaces And Abstract Classes 8x


    Whats the difference between an interface and an abstract class.

    DB:3.68: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 3.66

    DB:3.66:Difference Between Inheritance And Abstract Class 9s


    difference between inheritance and abstract class

    DB:3.66: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 3.66

    DB:3.66: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:3.66: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 3.66

    DB:3.66: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:3.66: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 3.65

    DB:3.65: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:3.65:Abstract Class And Interface???? ja

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

  • RELEVANCY SCORE 3.65

    DB:3.65: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:3.65: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 3.61

    DB:3.61:Java Interfaces 1a


    Java allows to put 'abstract' keyword while declaring an interface, but by definition interfaces are support to be abstract, so whether there is any specific meaning of declaring an interface abstract. I mean whats the difference between an interface and an abstract interface?

    DB:3.61:Java Interfaces 1a

    No difference whatsoever. I believe the "abstarct" keyword in interfaces is an ingheritance from previous versions

  • RELEVANCY SCORE 3.60

    DB:3.60:Abstract And Interface fa


    Dear Sir/Madam,

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

    DB:3.60: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 3.60

    DB:3.60:Java Programming 33


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

    DB:3.60: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 3.59

    DB:3.59:Abstract Class And Interfaces xz


    Hi Recently

    I attended a Interview ,Interviewer asked me what is difference b/w abstract and interface.

    I cud give answer ,,he said what if abstract class has all abstract methods.in this situation is ther any difference between abstract class and interface..

    i said there will be no difference in making all methods abstract and it is similar to interface.the only difference is at one point of time u can have a class can inherit only one abstarct class whereas interface u can have more than one interface....

    I want to know is my answer is right r not..please suggest is it correct and if any other ans please do reply

    With Regards
    Mahender
    Mahender

    DB:3.59:Abstract Class And Interfaces xz

    Stepping away from purely technical differences, there are some more fundamental ones.First there is a semantic difference. A base class says that any derived classes have an is a relationship with the base. For example you could have a base class such as Stream because derived classes are streams, but you wouldn't have a base class such as Serializable because you couldn't say that a derived type is a Serializable.Secondly there is the versioning problem. With an abstract base class you can add non-abstract members in future versions without breaking any existing functionality (save for possibly name collisions) because the base class provides the implementation. With an interface you can never add members because you will break any existing implementors. http://gregbeech.com/blogs/tech

  • RELEVANCY SCORE 3.58

    DB:3.58: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:3.58:Difference Between Abstarct Class And Interface 7j

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

  • RELEVANCY SCORE 3.56

    DB:3.56: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:3.56: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 3.56

    DB:3.56:Difference ???? xz


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

    DB:3.56: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 3.55

    DB:3.55: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:3.55:Regarding Dynamic Binding And Abstract Class pp

    hello Sumit.Tyagi

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

    Regards
    sricharan

  • RELEVANCY SCORE 3.54

    DB:3.54:Abstract Class And Interface z1


    What is most important thing about abstract class and interface.

    When to use abstract class and interface.

    DB:3.54: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 3.54

    DB:3.54:Situation That Describes Difference Between Usage Of Inetrface And Abstract Class x8


    Hi,
    Can anybody please tell me the best example or situation where we can chosse between interface and abstract class?Thanks, Smiley:)

    DB:3.54:Situation That Describes Difference Between Usage Of Inetrface And Abstract Class x8

    Hi Smiley3,
    I am marking this issue as Answered. If you have any new questions or concerns about this issue, please feel free to let me know.
    Thank you and have a nice day!Min Zhu [MSFT]
    MSDN Community Support | Feedback to us
    Get or Request Code Sample from Microsoft
    Please remember to mark the replies as answers if they help and unmark them if they provide no help.

  • RELEVANCY SCORE 3.54

    DB:3.54: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 3.53

    DB:3.53:Help Pls! 87


    Hi, can someone pls tell me what the difference between a normal class and an 'abstract class' is.

    Thanx!

    DB:3.53:Help Pls! 87

    Chris Evans just rang to call it off, apparentley he'd rather be seen with someone cool like Danny Baker and that my wife was too old for him.
    So I'll knock up a quick batch of proper nosh and meet yer all there. Hope you all like Pie and Mash Suchi, beautiful.

    Jamie

  • RELEVANCY SCORE 3.53

    DB:3.53: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:3.53: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 3.53

    DB:3.53: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:3.53: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 3.52

    DB:3.52:Difference Between Interface And Abstract Class? x1


    Hi,

    Can u plz explain
    at what scenarios we use interface and abstract class.?

    Thanks,
    B.Maruthi

    DB:3.52:Difference Between Interface And Abstract Class? x1

    If you had read the FAQ at the top of the forum home
    page you wouldn'y have bothered to ask this
    question.Anyways heres the link

    Read the question number 13 in this link

    http://access1.sun.com/FAQSets/newtojavatechfaq.htmlnice

  • RELEVANCY SCORE 3.51

    DB:3.51:Interface fd


    can any one tell me what is the actual difference between an abstarct class and interface.when do we use interface and when do we use abstract class in real time environment?

    DB:3.51:Interface fd

    don't encourage this nonsense

  • RELEVANCY SCORE 3.50

    DB:3.50:Difference From Design Perspective 9f


    Hi,
    Can nybody tell me the difference between abstract class and interface from design point of view. This questions waz asked 2 me in an interview.

    Tx.

    Naseem Khan

    DB:3.50:Difference From Design Perspective 9f

    Well. if you really need to know the details check
    out page 118 of the Java Language Spec. The summary
    is:

    - more than one interface can be implemented by a
    class.
    - an abstract class can contain implementation.That is not the big difference, but one will see it if one contemplates on this a little.

  • RELEVANCY SCORE 3.49

    DB:3.49: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:3.49: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 3.47

    DB:3.47:What Is The Difference Between Abstract And Normal Class k1


    What will be the difference if I replaced :
    public abstract MyWork {
    ....
    }
    [/code]

    by public MyWork { ........
    }

    THanks in Advance

    Tleis

    DB:3.47:What Is The Difference Between Abstract And Normal Class k1

    To clear all that up for those guys:

    An abstract class must be subclassed or instantiated as an anonymous class. It can have any of the same members as a regular class and in addition it can define abstract methods. Any abstract methods must be implemented by the subclass or else that class too must be declared abstract.

    An abstract class is different from an interface. Java gives you only a single ancester in your class hierarchy. You will force an implementation to become a descendant of your abstract class -- and therefore no other. In "object oriented programming", the term "an 'is-a' relationship" is used to describe that relationship between any subclass and its superclass. However you like to put it: this is the relationship you will be defining when you write your abstract class.

    - Steev.

  • RELEVANCY SCORE 3.45

    DB:3.45: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:3.45: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 3.43

    DB:3.43:Please Suggest 7p


    public abstract MyClass
    {
    public abstract void method1();
    public abstract void method2();
    }

    public interface MyInterface
    {
    public abstract void method1();
    public abstract void method2();
    }

    What is the difference between these two ?

    DB:3.43:Please Suggest 7p

    What exactly is your question? Are you trying to understand the difference between an abstract class and interface?

  • RELEVANCY SCORE 3.42

    DB:3.42: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:3.42: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 3.41

    DB:3.41: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:3.41:Abstract Class And Interface mc

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

  • RELEVANCY SCORE 3.41

    DB:3.41: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 3.40

    DB:3.40: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 3.40

    DB:3.40: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:3.40: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 3.39

    DB:3.39:Concrete Class ff


    Hi

    Could someone tell me what the difference is between an abstract class, interface class and a concerte class. Cant figure it out.

    Thank you
    David

  • RELEVANCY SCORE 3.38

    DB:3.38:Subclass Vs Concrete Class fs


    Hi,

    What is the exact difference between subclass and concrete class?

    What is the need in subclassing abstract class to again abstract class?

    Thanks in Advance,
    venu.

    DB:3.38:Subclass Vs Concrete Class fs

    Hi,

    U mean to say Concrete classes are instantiatable
    and every concrete class is a subclass of some
    super class.Plz clarify me if i am wrong.That's correct. But it's also true that every class--both concrete and abstract--is a subclass of some superclass, except Object which has no superclass.

    NOTE: The following is simply provided in the interest of completeness because I'm a ballsniffing pedant. It's not that important to what you're asking about, and may just cause more confusion. Feel free to ignore it.

    Also, it's possible to make a concrete class non-instantiable by having a single private constructor and throwing an exception from it, but that's a runtime issue--the compiler will let you insstantiate the class (only from within itself if the c'tor is private).

  • RELEVANCY SCORE 3.38

    DB:3.38:Diference Between Abstract Class And Interface cp



     
    Hi,
     
    I had a doubt on basic concept of interface and abstract class.
     
    I had idea of wht is interface and abstract class but there is case ,can any do justification on these case is
     
    Abstract class is a clas where some methods r defined and some are abstract methods.
    Interface is where all methods are abstract .
     
    but what happen if i try to maintaince all methods in abstract class as abstract which is equivalent to interface.?
     
    We go for abstract class if want to extend functionality of class.For interface if we wanna implement a new implementation.
     
    is there any other difference apart from this and other issues if we try to have all methods abstract .
     
     
    With regards
    Mahender

    DB:3.38:Diference Between Abstract Class And Interface cp

    Hi,
     
    Thnx for giving info.Actually iam looking for projct development point of view..In whihc cases i do go 4 developing abstract classes  other interfaces

  • RELEVANCY SCORE 3.37

    DB:3.37:Interface Vs Abstract Class 81


    hello
    what to use when between interface vs abstract class?
    and which one is better for decoupling and different version on software.
    regardsIt's Me

    DB:3.37:Interface Vs Abstract Class 81

    For a detailed discussion on this see:
    Abstract Class vs InterfaceJohn Grove - DSS, Senior Software Engineer

  • RELEVANCY SCORE 3.35

    DB:3.35:Difference j9


    difference between abstract class and interface

    DB:3.35: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 3.35

    DB:3.35: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:3.35: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 3.34

    DB:3.34: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:3.34:Abstract Class Vs Interface 9a

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

  • RELEVANCY SCORE 3.31

    DB:3.31: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:3.31:Interface And Abstract Class ac

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

  • RELEVANCY SCORE 3.30

    DB:3.30: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:3.30: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 3.29

    DB:3.29: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:3.29:Re: Different Between Abstract Class And Interface 77

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

  • RELEVANCY SCORE 3.28

    DB:3.28:Diff. Between Interface And Abstract Class 3s


    hi,
    Can any one tell me about diff between interface and abstract class in practical way.advanced thanks for ur response.
    -PVMVS

    DB:3.28:Diff. Between Interface And Abstract Class 3s

    This question gets asked all the time. I found lots of hits by searching this forum with the words: interface abstract class difference

    I'm sure google will return even more. Searching existing posts should always be done before posting.

  • RELEVANCY SCORE 3.25

    DB:3.25: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:3.25: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 3.25

    DB:3.25: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:3.25: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 3.25

    DB:3.25: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:3.25: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 3.24

    DB:3.24:Re: Difference Between Abstract Class Ans Interface 39


    Abstract classes have atleast one method abstract and interfaces have all abstract methods.

    If you are developing some application in which any entity can have more than one implementation, it is good practice to use an interface and implement the classes using interfaces.

    If some of the functionality of an entity is already known and other methods can have different implementations, then creating an abstract class is better.

    It's all a part of having a good design. Look around in the API docs and you'd find lots of abstract classes and interfaces. Try to figure out why they are so... I hope I didn't confuse you.

    Read the URL for better View

    http://java.sys-con.com/read/36250.htm

  • RELEVANCY SCORE 3.22

    DB:3.22:What Is Difference Between Abstraction And Abstract Class ? j3


    What is difference between abstraction and abstract class ?

  • RELEVANCY SCORE 3.22

    DB:3.22:Abstract Class Vs Interface ak


    hi,
    i know this is a very simple question but pliz answer it with implementation details.

    What is the difference beteen ABSTRACT CLASS INTERFACE?
    Just answer me when can a programmer use ABSTRACT CLASS when can he use INTERFACE.

    i need the situation not the theory,that are available in all java books.

    keep smiling...
    Deb

    DB:3.22:Abstract Class Vs Interface ak

    Interfaces are used to allow a class to have multiple personalities. A class can implement any number of interfaces and this will allow it to be any of those types of objects. (It's almost like multiple inheratence)

    An abstract class has to be extended and you can only extend one abstract class.

    An abstract class defines a general idea of what the object is. You extend it to fill in the details.

    An interface provides a framework for expected behaviour you provide the details of that behaviour.

  • RELEVANCY SCORE 3.22

    DB:3.22:Abstract Class Or Interface. Which One Is Better 77


    hai everybody,

    i have a confusion between choosing of abstract class or Interface.

    abstract class Abstra
    {
    public abstract void abst();
    }
    interface Inter
    {
    public abstract void inter();
    }

    looks almost same !!!
    which one of above is better to inherit for a class.
    and more importantly why ?
    Everybody says it's interface....but i dont understand what could be the reason.
    i want to know the reason if interface is better as compare to abstract class.
    why ? why ? why ? why ?

    DB:3.22:Abstract Class Or Interface. Which One Is Better 77

    a very good answer...get to know first of all whats the difference between Abstract class and Interface.

  • RELEVANCY SCORE 3.21

    DB:3.21:Serialize And Sequential Files. k8


    Hi all :)
    This may be a little abstract question:
    Is there any difference between any sequential file and a class file which implements the Serializable interface?Or can it be called a sequential file if a .class implements the Serializable interface?
    Thanx!

  • RELEVANCY SCORE 3.19

    DB:3.19: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:3.19: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 3.19

    DB:3.19: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:3.19: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 3.17

    DB:3.17: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:3.17: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 3.17

    DB:3.17: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:3.17: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 3.17

    DB:3.17: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:3.17:What Is The Difference Between Abstract Class And Interface jf

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

  • RELEVANCY SCORE 3.16

    DB:3.16:Abstract Class Vs Interface ? 9d


    hi all,

    can anybody help me.

    if i have an abstract class (full of abstract method definitions) and an interface(having same definitions).

    Now the question is in which situation we go for an ABSTRACT CLASS with full of abstract method definitions and in which situation we go for an INTERFACE.

    and other differences between ABSTRACT CLASSES and INTERFACES except Multiple Inheritence ?

    DB:3.16:Abstract Class Vs Interface ? 9d

    Hi,
    All the variable inside the interface are static and final(You can't change it).While in case of abstract class it is not so. And in abstract class you can have concrete method also while in interface all the method must be non concrete So its depends on your requirement.

    Regards,
    Alok

  • RELEVANCY SCORE 3.15

    DB:3.15:Difference Between Inteerface And Abstract 11


    Hi,Please Anyone can tell me What is the difference between Abstract and Interface?Where we can use interface and where we can use abstract?What is the uses of both?

    DB:3.15:Difference Between Inteerface And Abstract 11

    I agree with the all of the above, just adding one more thing:
    An interface is a pure abstract

  • RELEVANCY SCORE 3.15

    DB:3.15:Abstract Vs Interfaces sx


    hi i am looking for the difference between abstract classes and interfaces. i have refered a couple of books but nothing seems to satisfy me. and another thing when to use an abstract class and when to use an interface( other than multiple inheritence)

    thanks

    DB:3.15:Abstract Vs Interfaces sx

    In my opinion, Java sun programmers construct
    abstract classes in order to prevent some of the
    disadvantages of interfaces such that using only
    empty bodied method.It is a joke do not take it serious but it is really true that they construct abstract classes in order to prevent some of the disadvantages of interfaces

  • 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: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:3.15:Difference Between Interface And Abstract Class zk

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

  • RELEVANCY SCORE 3.15

    DB:3.15:What Is Difference Between Interface And Abstract? 3s


    Many time, I just confuse the purpose of interface and abstract.
    When should use interface or abstract in real world?
    Please give me the difference point alike point of both interface and abstract.

    Thank you.

    DB:3.15:What Is Difference Between Interface And Abstract? 3s

    Hi
    Take a look on this
    http://www.c-sharpcorner.com/UploadFile/yougerthen/104232008193919PM/1.aspx
    Reguards

    The complexity resides in the simplicity Follow me at: http://smartssolutions.blogspot.com

  • RELEVANCY SCORE 3.14

    DB:3.14: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 3.14

    DB:3.14: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:3.14: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 3.13

    DB:3.13:Difference B/W Abstract &Amp; Interface dx


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

    DB:3.13:Difference B/W Abstract &Amp; Interface dx

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

  • RELEVANCY SCORE 3.13

    DB:3.13:Concept Of Abstract Class &Amp; Interface fc


    Hi friends,

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

  • RELEVANCY SCORE 3.12

    DB:3.12: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