Why Interface is necessary in Java?

Hi,
we know interface is like a skeleton, that contains only method signatures and variables. Methods must be public, abstract and variables must be public static final.
simply we are implementing interface and defining all the methods in our class. we can do this without going to interface.
why we have this interface? please explain me with simple real time example.
Thanks and Regards,
Periyasamy

simply we are implementing interface and defining all
the methods in our class. we can do this without
going to interface.Huh?
why we have this interface? please explain me with
simple real time example.Do you mean "real-life"?
Example
There is no specified implementation type of the return value, and neither should there be one, so it can be easily replaced.

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hi,
why it is necessary that public class name should same as filename in java.
As I know that it is a convention, but I want the information why this convention is made.
thanx.

user13445117 wrote:
but suppose if i am creating a java file with default access modifire then we do not need to save the file name as a class name.So, your question is "Why does the rule about top-level classes being in a file of the same name apply +only+ to public classes"?
If it were applied to all classes, then we could never have two top-level classes in the same file. Doing that is generally not a good idea, but it might be useful from time to time. EJP already told you why it applies to public classes, and, since these are the most common by far, it's a fair compromise that it apply to them but not to other classes.
Was this the reason the original designers did it that way 15 or so years ago? Don't know, don't care, but it's one plausible explanation. Maybe it was just a balance between simplicity and clarity on the one hand, and flexibility on the other.
It's certainly not something I can see caring that much about, unless you're doing an in-depth history on Java, or writing an in-depth treatise on computer language and compiler theory.

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I am reading the NetWeaver Development Infrastructure, and noticed that due to the distributed development nature of Java, SAP recommend The Four-System Landscape for the development lifecycle.
Each developers has their own local development environment, that's why it is necessary to 'reconcile' the environment using one more layer of system. Although they checked out the particular Development Object, the necessary library from the central is being copied by DTR to the local environment. However, there are still possibilities that someone changes the library, or other classes that being refered. And we are not talking only about the business logic, but other object in the persistance level too. Let's say your program refered to a certain field in a certain table, but someone else had changed the field name. Or even worse, you want to get the setting value from a certain setting table, but someone else had deleted the value of that record (for whatever reason).
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Not only this, the setting of 'correct' IDE environment in each local PC must be done properly. Again, in ABAP you just need to install SAP GUI and it will be your development environment.
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What other people think?
rgs,
Hiroshi
ps: As you might notice, this thread is not marked as question. I am just curious of what other people think about this issue. There will be no points rewarded for the replies.

Hello Satya,
So if it's a 'mere' technical limitation, then there should be a way to create centralized development for Java
It might be an old mainframe environment, but from the development process point of view, centralized environment offers benefit where lots of versioning problem (library or data dictionary) can be solved.
I used to work in a distributed development environment to create a web based FI/SD/MM related application. We have tons of classic problem of '<i>it is working in my environment, but not in yours</i>' type of thing. With centralized (read: ABAP), version integrity problem can be reduced to minimum.
For the NWDI itself, I think SAP now moves toward embracing the open source platform to support the development environment. From what I've understood, Ant, for example will be used as the build tool. My personal opinion is, better if SAP creates it's 'proprietary' environment to centralized the java development process. Then it will save lot's of hidden cost during the implementation of new application/enhancement/maintenance in the whole supply chain.
rgs,
hiroshi

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Noob hardly expresses my incompetence here so thank you for your patience.

MacDyver wrote:
I am very appreciative for the assistance however it confuses me slightly more in that I do have a Roland Octa-Capture however it also connects via USB. I guess it is also useless
Articles I read state USB can theoretically carry 255 channels but everything else points to L/R Stereo.
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Why are you shouting?
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Why can't i install java on os 10.7, under install it says error something about java script

why can't i install java on os 10.7, under install it says error something about java script

If you can't get any software updates, there is something wrong and I would suggest reinstalling Lion.
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Is an audio interface really necessary?

Ok, right now I have my condenser mic hooked up to a phantom power and from the phantom power to the computer. All my recordings come out clear and loud. But my friend told me that if I get an audio interface, my recordings will sound much better. Well is it true? What are the benefits of an audio interface?
thanks

I actually use a variety of interfaces. Yesterday I spent the day with one from M-Audio and, while not as good sounding as the RME in my sig, the results were surprisingly good.
While there are a number of technical reasons why interfaces will sound better than going into the computer directly, aside from the technical mumbo jumbo, I do find a big jump in sound quality using an interface vs. a direct input, and not simply the difference between one flavor preamp and another.
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kbeartx does make an excellent point, one of two that frequently degrade conversations about gear. Of course experience is all important! And the other: "it's all about the music," as if discussing equipment suggests otherwise. Still, equipment, and discussing it, has a value. Equipment and experience are not mutually exclusive.
It's like surgeons speaking about scalpels. An experienced surgeon will do a better job with a steak knife than an inexperienced surgeon will do with a finely-honed scalpel. Still, no one would denigrate any surgeon for seeking the best tool available.
That's all this is.
Inifinity239 has a steak knife and is wondering if a scalpel works better. As someone who has used both (to continue this now very tortured metaphor )... I would say of course!

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Hi
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Hi,
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here is the code sample for same:
Collection c = Collections.synchronizedCollection(myCollection);
synchronized(c) {
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while (i.hasNext())
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If at the first place I am getting all the methods synchronized by calling
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Why Interface is necessary in Java?

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