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Hi this is really hard.

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Once again welcome to the next video of this Carleen for now Mendel's.

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In this video we will talk about voter interfaces in case of Cartland.

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So let us first check out the practical example and then the Tuti.

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So here insert the intelligent ID.

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This is the example that we took in the previous video made about the abstraction in Gears of Cartland.

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Now suppose if I change this abstract open class to let's see interface and now the interface is not

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a class.

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Always remember this.

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It is something like a listener that you want some service such as on click of button.

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Something should happen on touch of a keyboard something should happen.

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So in that case the listener is actually the interface right.

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You want some short term or temporary service.

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So in that case we create the interface as for example in Android.

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Suppose someone click on a button.

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So on click of a button something should happen right.

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So we implement the on click method in case of Android.

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So that is the main purpose of interface in case of Cartland as well.

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So here let us change the name of interface Let's see might in Duffys listener.

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Right.

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And now here Vontae What do you define inside an interface.

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Is actually by default abstract in nature such as that.

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Let's say name string.

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Well it should not be name here because we are using the interface but it's a variable name so let it

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be named by default right now by default whatever you declare inside the interface is actually abstract

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and also open in nature because abstract variables and methods are by default open in nature that we

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saw in the previous review right.

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And this abstract is redundant.

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So we need to remove it as well and also abstract keywords and also abstract methods and also the variables

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should not contain some be FOID value like here.

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Let's say I mean name like this.

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So the abstract variables should not contain some initialized value.

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It should be a declaration like this so that it is removed as well because it is redundant.

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So here I have simply written a comment statement properties in gifts or interface or abstract Bideford

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right.

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And now suppose let us define a function.

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Let's see it or let's say on Glee.

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And here suppose if I define a body.

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Now if you define a body then this method is actually a normal function which is actually public in

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nature.

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But in this case it is not final in nature because in case of an Duffys nothing is final.

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Everything is open in nature.

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So this method is basically is by default open in nature.

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It is not final.

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So always remember in is in Duffys nothing is final.

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Everything is open in nature.

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So let me write a line for you.

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So the normal methods are public and open Bideford not final.

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Always remember.

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And now here this public and open keyword are redundant.

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So let us remove it and now let us define one more method.

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Let's see a function of.

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On page on pecial for which something should happen.

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Now here if I define here the body and declare here abstract then the compiler is again not happy because

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the abstract metrics cannot contain the body right.

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So here either I have to remove this or I have to remove this from here.

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But but I've tried this method to be abstract in nature right.

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So here they really do is I would simply remove the body now since it is abstract in nature.

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So you have the compulsorily or what I did inside the class that implements this interface.

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And now this was all about the properties inside the interface abstract methods and also the normal

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matters.

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And now suppose I have a class of Indian.

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Let's see let's remove it here and there doesn't modify the code.

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The class of bargain.

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Now suppose if I want to implement this in Duffys for this button so what I will do is I would simply

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use Blasberg then go alone then simply use my interface listener.

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Now this is actually the interface.

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Suppose you want to inherit some classic legacy person then for that you need to use the syntax isn't

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followed by the primary constructor.

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As we did in the previous videos.

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But if you want to implement the interface then you just have to specify galloon forward by interface

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name.

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There is no primary constructor here.

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Just because the interface cannot be instantiated.

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So here I've simply written the command line.

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You cannot create the instance of the abstract class.

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Let's make it in Duffys so the interface is similar to the abstract class cannot be instantiated.

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What I'm talking about is inside the main method.

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You simply cannot define that.

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Let's see may object equal to might in Duffys list.

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You can not do it because my interface is listen that can not contain a constructor as well.

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It is just an interface not a class.

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So always remember it is similar to Abchurch classes.

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The interface cannot be instantiated as remove it.

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And now here Legos move the person as well.

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So this is the syntax to get all the properties of this.

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Mike Duffy is listed there inside the class of button.

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And now let's call it my button as of now just to avoid any confusion.

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And now here it shows some error that if you are using the interface here then you must override this

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abstract method that is on edge.

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And also this abstract variable name.

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And now here this abstract abstract keyword is redundant.

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So again metrics in interface are abstracted by the.

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So to rectify this error we need to override this variable name and also function on stage because they

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are abstract in nature.

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So I will simply override.

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Let's see what I divide.

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Name other types of string and simply assign a default value with a dummy name.

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It is totally up to your choice.

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And now let us all read this abstract method as well.

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Function on page.

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So here I will simply use overdyed keyword SPEEs function.

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Let's see.

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On page so here the intelligent Id simply creates a placeholder to do for us.

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I simply define our own code right like this.

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Now coming to this point function on click.

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Now this function on click is not abstract in nature because it has a method and body so it is actually

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behaving like a normal method.

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So if you've warned it is totally your choice.

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You override that method or not.

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If you want you can also override it.

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It is totally up to your choice right.

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And if you want you can also call the support implementation of this method like Supernaut on click

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method.

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So as of now I don't want it.

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So that does remove it.

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You may or may not override this method.

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Right because this is a normal method.

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Now inside the main method what I'm going to do is simply create the instance of this class of my button

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because this my button is actually of the type of plus so began instantiated value.

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Let's see.

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And after this I would simply call my button and Dorte.

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Let's say on that great.

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So this was simply too good.

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This mentored president he had on pitch and also I will call my Verdon dark legacy on Glick.

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And this was simply very good this method.

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But as here.

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This on klick.

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Now let us define our record here.

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Let's see then.

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Martin was just.

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And he had Franklin as well.

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Burton was right.

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And I suppose if I had the court right now then these two statements is simply going to print the was

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just and also bartend was plugged in the output gunsel.

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So here in the output we get burdened was plagued button was dust and leaked like this.

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And now suppose inside the on click method.

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Suppose I have some print statement.

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Let's see Brant line on click interface boards right like this.

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So this is the opening line statement inside the on click method.

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Now suppose I want to print this statement as well.

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So far that what I really do is insert the limiter method inside of my Button class.

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What we do is I would simply use the super keyword superdog and I I'll simply call on click Metford.

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So this will simply Paragould the superclass method that is this one.

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Now remember this is not the class right but still we are inheriting all the properties of my in Duffys

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listener.

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Inside my button class.

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So they're just not called so in the output we get but then was just then only in Duffys scored but

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it was scored and then button was clicked.

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So this is how we call the superclass method.

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Right.

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Like we have done here superdog on click.

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Now if you want to and also remove this on click chord here.

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It will show no error.

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Right.

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But if you remove this on touch method then the compiler is not happy because this on this method is

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actually abstract in nature.

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So you need to override it.

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Anyhow here inside there did a plus.

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And now suppose I have one more in Duffys.

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So let us copy this in Duffys.

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My second in Duffys listener Ahlers lairds trimmed down the name.

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My second in Duffys right and now inside both the interface.

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Let's just modify our code.

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So here I will simply remove the variable name and also here name.

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And now I will simply convert this function on edge into the normal method.

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So I would simply define the body as.

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Let's see if Parentline aren't actually scored from my second interface on actual scored from my and

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in Duffys.

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Now similarly here I will.

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So here I have simply mortified my chord inside my industrious listener I am having on Dutch abstract

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matters without any body Nasima.

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I am having in inside my second interface.

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But it is not behaving as a normal method.

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It is no longer abstract method.

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Now this method and this method of yours truly seem right.

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So suppose I want to implement both the list inside my board and clothes.

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So what we do is this is our first listener and then I will simply give a coma and then implement my

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second interface like this right.

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And here it is.

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Will this statement.

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And now let just remove the chord as well.

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Here and now here it shows some error that you need to implement the abstract method so simply place

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it and go implement the members and English sure you two options.

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Mike Gardley in my interface listener.

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My second Duffys.

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We need to override this on Bush method which is actually abstract in nature so ask but our expectation

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that EDID should have been gone.

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But here if you notice the error is not gone.

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But as per the rule we have simply overridden this abstract method no rest of the methods are actually

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normal amateur's that should be optional to override such as on CLI mattered and also on the method

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of the second interface.

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But here we are using to interface now these two dollface have two amateur's on edge and on Glee and

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in one of the keys we have on Desch mentored as abstract.

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So we need to override this on page Metford complicity inside of my button plus but Varda bold on click

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mattered.

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This is normal my third here and this is again the normal method.

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No aspart at all.

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If there are two interface and there are two normal amateur's all of the same name inside the interface

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then you need to override that method as well.

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So here I have to simply press or enter and simply inherit the on click method here like this.

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So this rectifies our error.

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Right now supperless.

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I created the instance of my button like this and call my button on stage and my but and on click right

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now if I simply want to call this button dord on touch method then it will simply go into pretty good

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this method down the side inside the main button plus and if I want to trigger a superclass method then

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I would simply use superdog on page.

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So this statement is similar to good.

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The on page method here because this is the normal method and this is the abstract method without any

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body.

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So there is no point of this method being called because this method don't have any code.

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And here I have some code right.

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So this statement will simply trigger the superclass on Bash method of my second interface that has

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some Vardi.

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And now suppose this statement is executed Mayberg and or unclick.

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So this will simply trigger this local method off on leg press and inside my button plus.

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So here if I call Lexie's soup it dawned on click.

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So what will happen it will simply show some error because the compiler will be confused.

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That are superdog on click Metford is actually present in boot that case that is in this interface and

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also inserted this in Duffys so it gets simply confused which meant to call.

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Right so in that case we have a solution here.

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We can simply define super.

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I simply pass the name of the Duffys super.

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My interface listener got on click and again if you want to call this Mazak an interface on click Metford

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then you can simply call super and simply pass the name of my second interface Dorte on click.

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Right so these two statements are simply going to trigger the respective on click methods present inside

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the interface.

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Here and here like this.

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So always remember this while you are using there to interface and if the interface contains the same

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third name.

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So how to handle that situation.

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I just showed you in this example.

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So this was all about the practical example.

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No need to jump back to the tutor Dickel example.

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So the interface can contain both normal methods and also abstract methods.

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So always remember this.

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It can contain normal as well as abstract methods but in gesso property they can contain only abstract

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property that is you cannot initialize any variable inside the interface.

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Novels are going forward.

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The indices are not a class.

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So do remember this and now similar to the abstract class.

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You can not create the instance of the interface because the interface is not a class.

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It is something different thing that only provides a short term sort of his such as a button click on

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touch when you check the checkbox when you try to open their dialog box.

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And something like that.

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So it simply provides a short them service right there in Duffys.

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So this was all about the interface in case of Cartland.