Hi All , Will Java supports Multiple Inheritance classes???

Hi All ,
Will Java supports Multiple Inheritance by classes???
Thanks in advance,
Prakash

No, Multiple inheritance would look like
public class A extends B,C {(You can do that in C++, but it's rarely a good idea).That's not true at all. It's not inherently harmful, in C++ or any other language. It's entirely possible to do it correctly when it truly makes sense.
Java just guarantees that nothing bad can happen to you by only allowing multiple inheritance of interface. You can't ever have multiple inheritance of implementation, that's all.
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Similar Messages

How java support multiple inheritance by the use of interface.

As per my understanding, Interface is just having the signatures of the methods not the implementation.
So How java support multiple inheritance by the use of interface?
Answer 1: we can institate interface reference by its implemented
class.
          �� interface inf...
          �� class aa implements inf..
          �� class bb implements inf....
           Now, inf i = new aa();
           inf i = new bb();
Answer 2: We can extends as many interface as we want in the
single
           interface.
           i.e. interface infFirst....
           interface infSecond....
           interface infThird....
           Now ,
           interface ingMulti extends infFrist, infThird...
By above two answers its not prity clear as per the multiple inheritance in C or C++.
           i.e.
           class first{
           method abc();....}
           class second{
           method bbc()......}
           class multi::first::second{
           we can call to abc();.....as well as bbc();
-Please give your important suggstion on the same.(Hope I explain it well.)
-Jeff

The keyword implement is used only for interfaces not
for abstract class. If i am wrong correct me.I believe your right, but I will double check.
As for the multiple inheritence think about the following code:
class Animal {
    // Animal generic stuff in this class
interface Eat {
    // Generic stuff that models eating behavior
interface Runs {
    // generic methods that model running behavior
public class Horse extends Animal implements Eat, Runs {
    // Stuff specific to a horse
}The Animal class is generic but has stuff in it common to all animals.
The Eat interface models behavior that is generic to eating, all living things have to eat something to survive. Herbavore are different from carnivores.
The Runs interface models generic behavior to running, such as speed. A cheeta definately runs faster than a human.
This brings us to the Horse class. It extends the Animal class because it "is-a" animal, and it implements the eat and runs interface because they are behaviors a horse has.
I hope that helps.
Extending an abstract class is the same as extending a regular class with the exception you MUST override all abstract methods in the abstract class. Thats not too difficult but I believe when designing classes, designing an abstract can be more diffecult than modeling the base class, and generic behaviors in interfaces. JMO.
JJ

Why java does not support multiple inheritance ???

Hai friends ..iam new to java .. i have doubt ..plz help me
Why java does not support multiple inheritance ???

The reasons for omitting multiple inheritance from the Java language mostly stem from the "simple, object oriented, and familiar" goal.
To understand multiple inheritance, the learner needs some level of expertise like virtual derivations etc in c++. Multiple inheritance will allow method duplication, and throws the learner into confusion which method might be called by the compiler in which scenario at run time.
Even though this answer seems to be funny, this is the actual reason why java omitted multiple inheritance of classes.
But java support multiple inheritance of interfaces. Multiple interface inheritance allows an object to inherit many different method signatures with the caveat that the inheriting object must implement those inherited methods.

How does Java achieve multiple inheritance using interfaces

Java does not allow multiple inheritance through classes as classes might contain methods with same names. what happens if a class implements two interfaces with same method names?
I am really confused abt this? Can anybody help me out?
Message was edited by:
vijkris

yes to avoid the ambiguous functions which can result due to multiple inheritance of classes like in c++ , java doesn't have this through classes. But if you have same method (both return type and parameter) then java doesn't bother and it won't complain as ultimately only one implementation is possible in deriving class even though method declalaration is there in both the interfaces. If return type changes then it won't compile as it can't overide the both methods as they have same name and different return types. thats why inside interfaces they restricted the implementation of methods so that it can work fine in ambiguous scenarios.

Will OBIEE supports multiple authentication

Hi All,
Does OBIEE 11.1.1.5.0 supports multiple authentication, at present in my environment we have configured LDAP, where a number users and groups are accessing obiee, we do not have some 3000 non obiee users, for these users also i have to send delivers. So my question how can i achieve. At present i am able to send delivers to obiee users.
Please provide information on this
Thanks
sreekanth

Hi,
Yes it supports multiple authentication.
For more refer,
http://docs.oracle.com/cd/E23943_01/bi.1111/e10543/privileges.htm#BABDCJBH
Thanks
Deva

How Java does not support multiple inheritance

Hi,
I have got a small doubt....
Generally it is said thatjava does not support multipleinheritance.I agree.
But then we know that every class in java by default is a sub class of Object class then how is it possible to inherit one more class using extends keyword.
I am confused?
Akshatha

Generally it is said thatjava does not support
multipleinheritance.I agree.Generaly, this is wrong. Java does support MI, just not MI of implementation. You can extend as many interfaces as you like.
But then we know that every class in java by default
is a sub class of Object class then how is it
possible to inherit one more class using extends
keyword.It is not possible. You can only extend directly from one single class. If you extend from something else than Object, you're not directly extending Object anymore.

Will java support swings along with sip protocol

sir i want the java and sip protocol to be used aside by aside by aside

Do you mean you want do use SIP from Java? Google for "sip java" and e.g. the first hit is about a SIP API for Java.

Enumerate multiple inheritance scenarios and their java equivalents?

hi,
ppl have often said things like
"java doesn't support multiple inheritance but this is ok, since there are other mechanisms for doing the same thing (by which we nearly always mean interfaces)"
how solid a statement is this? are there any formal methods available eg smt like "over all possible inheritance trees over all possible classes, only a handful of cases are distinct when viewed from the converting-to-single-inheritance scheme"?
the two things mentioned as harder to workaround are mixins and the diamond problem - are there more?
also what other mechanism apart from interfaces (if any) are useful?
any help appreciated,
asjf

What I say is that it doesn't matter since there is
almost never any need for MI. Most of the time it is
used it is used because the developer/designer did not
understand what they were doing and it should not have
been used in the first place.
That leaves one with very few cases where it should
ever be used. And that coupled with the fact that a
developer should never use it unless they are very
experienced (so that they actually know that it should
be used,) means that practicing programmers should
leave discussion of such usages to scholarly
journals.thanks :) I guess my problem is that often with computer stuff you don't have to rely on other peoples experience about things - you can go and test it yourself
I've done very little C++ development, and so have never come across real-world multiple inheritance. I bumped into the first situation with some java code where it might've been a neat solution recently but this could easily fit into the "designer did not understand what they were doing" category from above..
will have a casual look around the scholarly journals if I can find any that look promising :)
asjf

Multiple Inheritance of Class problem

I want to inherit two classes in my class
Since java does not support multiple inheritance of java classes , only can implement java interface , how can I achieve this .

I too have a dream.
Someday I want to see a design that uses multiple inheritance correctly. And as long as I am dreaming it might as well be a design that is not dependent on legacy applications.
I strongly suspect that it will forever remain a dream.

Multiple inheritance in Java

Why it is sometimes said that interfaces provide a form of multiple inheritance?
Do you agree that interfaces can provide multiple inheritance? Explain.
Some people say that Java does not support multiple inheritance, and others: a class can implement more than 1 interface. Isn't that multiple inheritance?
Thanks

>
Some people say that Java does not support multiple
inheritance, and others: a class can implement more
than 1 interface. Isn't that multiple inheritance?Sort of, but you don't inherit any implementation from an interface.

Multiple Inheritance

Hello,
I have been programming Java for last year,
evolved in quite some skills with it, and
really think it is great...
However, I was shocked to find out that there
is no multiple inheritance feature.
I know it is rare, and my case proves it
(1 year now, I never needed it)
HOWEVER, when one needs multiple inheritance,
then they really do need it.
I have interfaces which I would like implemented
in their respective class (ie ISomething be
implemented in CSomething), then some classes
I need to implement many of those interfaces...
Now I am forced to have those classes extend
multiple interfaces, and duplicate the interface
implementation code inside each of them.
I dont mind a little bit of copy/paste, nor
do I care about the compiled classes being
slightly bigger, BUT the problem is that
when I need to change some behaviour in those
interfaces, in the near (or far) future, I will
have their implementation scattered in many
classes... This is dangerously error prone and
not proffesional at all... And I do not think
that including multiple inheritance in the language
could be more error prone than this...
I think the Java team does a 100% perfect brilliant
job, but at this specific point, they "over-tried"
to "protect" the programmers from themselves...
Well, thats all,
I think some next version of Java should support
multiple inheritance. And the Java "warning" could be :
"if you havent missed it till now, then you probably
do not need anyway, so do not bother using it just
because it exists"
Thanks for reading my thoughts,
Dimitris

Personally I never need multiple inheritance of code and I try to avoid inheritance of code whenever possible. A common mistake in OO is too use inheritance as a way of reusing code. Code reuse is much easier, cleaner and more powerful by using composition instead. Only use inheritance for polymorhism (to use multiple implementations for the same interface). An example:
interface A {
void ma();
void maa();
interface B {
void mb();
class C implements A, B {
private A a;
private A c;
private B b;
public void ma() {
    a.ma();
public void maa() {
    c.maa();
public void mb() {
    b.mb();
}This is much more powerful than code reuse through inheritance. In this example I use one method from 'a' and one method from 'c' when I implement interface A. I can change the value of 'a', 'b' and 'c' during runtime, and I dont have to reuse all the code in 'a' and 'b', I can select which code to reuse. This is the power of composition and interfaces. Note that I only access 'a', 'b' and 'c' through the interfaces A and B, never directly through their implementations.
I would recommend you to look at your design and start to think about interfaces and inheritance, not about code reuse though inheritance.

Doubt on Multiple Inheritance

Hi all,
I am confused by the java statement that "By using interface we can achieve multiple inheritance bcoz java doesn't support Multiple inheritance".
Yes.Ok java doent support Multiple inheritance. Now we know that inheritance means that "one object acquires the property of another object".
So how can it is possible achieve Multiple inheritance by interface.
Interface that contains just undefined methods like below code.
interface Member1
     public void eye();
     public void nose();
     public void mouth();
interface Member2 extends member1
     public void neck();
     public void hand();
     public void stomach();
interface Member3 extends Member1,Member2
     public void leg();
class Man implements Member3
     public man()
     Member3 ref=new Man();
     // Here Implements all 7 methods.
Is the above code defines multiple Inheitance?
undefined methods are eye,nose,mouth,neck,handand stomach are fall in Interface Member3 .Yes. But Inheritance means that one object acquires the property of another object.Property means that code and data.
In here, there is no code just declarations of method which is not to be a code .
So How can we say interface achieve multiple inheritance.
Please any one explain and clear my doubt with simple example.
with cheers,
G.GandhiRaj.

Multiple inheritance is about aquiring both behavior and attributes from two or more sources. A lot of times, this "is a" relationship is confused with "has a" relationships.
For example, a Book "has a" Page. A Book "is a" Publication. So multiple inheretance in this instance would come from stating that a Book "is a" Publication and "is a" PaperProduct. In this example, you could redesign your model and state that a PaperProduct inherits from Publication. However, a Book doesn't have to be limited to being a PaperProduct, it can also be an ElectronicProduct, thus inhereting attributes and behaviors from this new class as well. In essence, the Book can exist in two forms simulataneously (as many actually do). So you still have the need for multiple inheritance - perhaps.
Interfaces define the behavioral aspects of multiple inheritance. You loose the aquisition of attributes from base classes. In many cases this is acceptable. For the first time I recently found a true need for multiple inheritance in one fo my Java apps. Some would say that my data model is poorly designed then. So I tried restructuring the model and that solve the problem.
It is probably a good idea to completely understand your data model from many dimensions first before resorting to the copying of attributes like I almost did. Don't be locked into a design too quickly. Be willing to change your mind and you will probably find a solution that works.

Question about multiple inheritance

Why does java not support multiple inheritance, but also give you the ability to use interfaces?
I've done a quick search on here which turned up the same thing as the books on java I've read - they tell me that java doesn't support multiple inheritance, and that it supports interfaces, but not why.
And from what I can see, the between multiple inheritance and single inheritance + interfaces make them seem almost equivalent, especially when you consider abstract classes. So why did the java designers make this decision?
Edit: Just to say I've never programmed in an OO language that supports multiple inheritance, so I've never had to deal with it. Also, single inheritance has never crippled any of my designs (not that there have been that many), I'm not whingeing, just asking.
Message was edited by:
Dross

Why does java not support multiple
inheritance, but also give you the ability to use
interfaces?It does support MI, just not MI of Implementation.
why.
class Beasty { }
class Horse extend Beasty {
public void gallop() { System.out.println( "horse" ); }
class Donkey extend Beasty {
public void gallop() { System.out.println( "donkey" ); }
class Mule extend House, Donkey {
Mule mule = new Mule();
mule.gallop();what would this print out.
MI of implementation makes life harder, but adds very little to the party. So why add it?

Alternatives to multiple inheritance for my architecture (NPCs in a Realtime Strategy game)?

Coding isn't that hard actually. The hard part is to write code that makes sense, is readable and understandable. So I want to get a better developer and create some solid architecture.
So I want to do create an architecture for NPCs in a video-game. It is a Realtime
Strategy game like Starcraft, Age of Empires, Command & Conquers, etc etc.. So I'll have different kinds of NPCs. A NPC can have one to many abilities (methods) of these: Build(), Farm() and Attack().
Examples:
Worker can Build() and Farm()
Warrior can Attack()
Citizen can Build(), Farm() and Attack()
Fisherman can Farm() and Attack()
I hope everything is clear so far.
So now I do have my NPC Types and their abilities. But lets come to the technical / programmatical aspect.
What would be a good programmatic architecture for my different kinds of NPCs?
Okay I could have a base class. Actually I think this is a good way to stick with the DRY principle.
So I can have methods like WalkTo(x,y) in
my base class since every NPC will be able to move. But now lets come to the real problem. Where do I implement my abilities? (remember: Build(), Farm() and Attack())
Since the abilities will consists of the same logic it would be annoying / break DRY principle to implement them for each NPC (Worker,Warrior, ..).
Okay I could implement the abilities within the base class. This would require some kind of logic that verifies if a NPC can use ability X. IsBuilder, CanBuild,
.. I think it is clear what I want to express.
But I don't feel very well with this idea. This sounds like a bloated base class with too much functionality.
I do use C# as programming language. So multiple inheritance isn't an opinion here. Means: Having extra base classes like Fisherman
: Farmer, Attacker won't work.

Hi
PandoraElite，
You can inherit from multiple interfaces (and use explicit interface implementation), but not from classes in C#. You can almost simulate it:
In C# we don't support multiple inheritance
http://blogs.msdn.com/b/csharpfaq/archive/2004/03/07/why-doesn-t-c-support-multiple-inheritance.aspx
What would be a good programmatic architecture for my different kinds of NPCs?
In your scenario, we can define some interface ,An interface contains only the signatures of methods, properties, events or indexers. A class or struct that implements the interface must implement the members of the interface that are specified
in the interface definition.
How to use? Please refer to the following article.
http://www.codeproject.com/Articles/18743/Interfaces-in-C-For-Beginners
Best of luck!
Kristin
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Multiple inheritance crack

hi,
Its known that java doesnt directly support multiple inheritance (though can be achieved through inner classes). It is also known that any java class is a sub-class of java.lang.Object. Java allows us to subclass any one class, but its already internally subclasses from java.lang.Object !! how can this multiple inheritance work ? please write to me at [email protected]

hi,
Its known that java doesnt directly support multiple
e inheritance (though can be achieved through inner
classes). It is also known that any java class is a
sub-class of java.lang.Object. Java allows us to
subclass any one class, but its already internally
subclasses from java.lang.Object !! how can this
multiple inheritance work ? please write to me at
[email protected]
A java class inherits directly from Object if, and only if, it does not inherit from another class. Consequently each class inherits from Object, but not necessarily directly.
Sylvia.

Hi All , Will Java supports Multiple Inheritance classes???

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