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High they're not us look at something called bonded by parameter.

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We know what the type parameter is.

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And we also know what a genetic type is.

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We know that genetic types gives the client code the flexibility to instantiate them that any type argument

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.

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So the problem lies with that plan but sometimes we might want to put some restriction on the kind code

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with regards to what type argument they can use while instantiating a generic like unglue that we can

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use it bownde a parameter the Bonder type an amateur is simply a parameter with one or more box.

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And here is the syntax.

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We have the byte barometer followed by the word extents which is then followed by one or more bonds

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which are separated by Ambersons symbol.

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On Here is an example of how the generic class called GenericsDemo excitable.

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And here the bomb for the type parameter is next.

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This means that the bite argument has to be a list or one of its subtypes.

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So we can have something like this with genetics that is instantiated using that type argument list

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or we can also have genetics to instantiate or to use in some types of list such as an idealist are

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linguists.

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But if we do this we get a compiler error as collection Binoy is not a populist.

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We know that it is a supertype awfullest.

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So it's got to be either the bone itself or one of its supples on a dime of this letter will also be

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a shock to this although as we saw in the syntax a bike parameter can have more than one bone.

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In practice you will mostly encounter only single boner by parameters.

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Now apart from restricting the glance on repipe arguments they can use a bone also allows its class

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to access them but that's defined by.

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For instance if we consider this example here we have the generic class.

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Generics don't have them either.

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Go with the parameter columnist's under stype is the type parameter.

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Now within this matter we are invoking the seismic third on the list immediately and when we do that

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we get a compiler error.

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And that's because here we are using only that type parameter uncompiled her just does not know whether

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the type argument would include the method size or not.

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But if you use a bounded type parameter where d extends the list interface then compiler will not have

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any problem as sys method is declared in the list interface.

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So that's a benefit you get in using bonce you can access their methods.

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But note that it's got to be a method in the bonus's if it is a method specific to one off it's subtypes

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then we once again get a compiler error.

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Now that has to do with type in Asia.

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We discussed pipe behavior in an earlier lesson.

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There we said that in the bytecode compiler would replace the type parameter with the pipe object right

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.

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However in this particular case since the type parameter extensive Baun the pipe parameter would be

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replaced by the bond itself.

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So in this example compiler will replace beat with list so the code within the government that can only

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use methods declared and then listen interface.

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If you have to use the methods declared in a subtype awfullest then you need to typecast to that particular

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supply.

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Otherwise you will get a compiler error on herer bones that are considered valid.

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A bomb can be a class or it can also be an interface not you look at the syntax Veals the keyword extents

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.

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That is we see some type parameter extend some ball and that applies to interface too.

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So you cannot use a word like implements just because the bond is an interface.

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So the keyword X does here works for both classes.

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USB plus interfaces next to bone can also be an enim which we will discuss later on finally.

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It can also be it Behrami Christ like so it can be that I'm type 2.

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And here's an example.

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Here the Bondy's it.

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But I mean cross-slide.

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Later we tried to look at more practical example of this unhidden bones that are invalid.

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It Baun cannot be primitive.

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No recall that type argument cannot also be a primitive case of primitives are not in love at all and

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a boat cannot be an update.

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So just keep that in mind.

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Undernote a few more specifics that we need to be Aguiar off with respect to bonder type parameters

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.

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First one is that if the type parameter has multiple bonce then the type argument must be a subtype

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of all the specified bonce.

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For instance in this class definition the right barometer extends both the list and Serializable interfaces

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.

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And this is the first instantiation would be invalid as the type argument list is not Issel type of

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serializable.

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It is fine with the Fussball but not with the Serializable interface.

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But the second instantiation is valid as other list is a subtype of both list as well as serializable

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.

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Next off the bonce is a class then it must be specified first.

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Otherwise you get a compiler error.

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No offense Bondies a class then remaining balance must be interfaces.

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In other words you cannot have more than one class among the list of bombs.

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Not that you can hold more than one interface and you can how only interfaces to not the bounds of final

79

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class on any name.

80

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Then the pipe argument would be the bonus.

81

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That's because final class does not have a subclass on enum is essentially any final class too.

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So those are specifics that we need to be aware of.

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Now let's go ahead and do a very quick demo of some of the stuff you saw in this lesson.

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OK here we are in the genetics demo class and we're going to test most of the stuff that we have seen

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in the lecture.

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So first thing yes let's just go ahead and make this a genetic type which should be under to make it

87

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bounded by parameter in its extent.

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That's what we have seen in the lecture.

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And here let's instantiate that generics them all.

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Now it is a Democrat state next to the last one.

91

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OK so that is valid.

92

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So it has to be a list so the list is up bound so it has to be the Bonder itself or one of its subtypes

93

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.

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So that is good and this is also good on our list but as we have seen it as collection then we get compilation

95

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error.

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That's because collection is a supertype off the bomb.

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In this case.

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OK so that's one thing that we looked at.

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Next we also said that we can access the methods and the bug.

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So if you do this here we have the there look at this and here that by parameter is steep.

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So on we are accessing the IDE matter and the list here the variable name is just a list but we are

102

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trying to access the add method in the list interface.

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Now we are getting type evasion.

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The compiler will replace every instance of B with a list.

105

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OK that's smart the compiler does.

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Spout off.

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I put it here since in this case it would replace the type with the boundaries set.

108

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If the bond was not there then it would replace with object.

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So in this case it would replace with D and we are able to access augmented.

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Now remove this.

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The T.M. this.

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So in this case as you can see we get a compilation error and we cannot access the add method in the

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list any more because the compiler just doesn't know that the type argument will be and this or not

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.

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How about if we extend less than we are regarding the compiler that the add method would be there now

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.

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No in order to make it work we have to use construct like this.

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That's the only solution that we have here or we need to make it a bounded by parameter.

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Now that's one thing and let me just you know this

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.

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Then we look at a couple of invalid Bonnes.

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So this is not going to work.

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If it cannot be an array.

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Similarly it cannot be a primitive.

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So once again we get a compilation error.

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Next below get some specifics.

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One of them is when we have multiple bones like this serializable.

128

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So these are two interfaces.

129

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Then the pipe argument has to be the bone or one off its up apps on it has to be a subtype of all of

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these.

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So

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make a list.

133

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So this would give a compilation error because the second one is fine.

134

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OK so the list is fine but it is not a subtype of serializable.

135

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Now if you make it out a list then there is no compiler because this is a supply both.

136

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Both of these interfaces.

137

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OK so that's one of the things one of the specifics that we have seen and the next thing was you said

138

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that if there is a class then it's got to be the Fussball.

139

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OK so this is fine.

140

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Now let's make it like this.

141

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So Serializable an idealist.

142

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And as you can see we get a compiler error here.

143

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OK so that's not how I end.

144

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You can also how more than one class.

145

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Even that was mentioned.

146

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So you can do this.

147

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So even if we import this you can see we cannot utter dick.

148

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So we can't have two classes here.

149

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OK so that Sanderus for this demo.

150

00:10:54,150  -->  00:10:56,010
So we basically looked at everything.

151

00:10:56,010  -->  00:11:01,800
Now if it is a final class like string then the R-Type argument has to be the bond itself.

152

00:11:01,860  -->  00:11:03,970
So we discuss that also.

153

00:11:04,050  -->  00:11:04,950
So that's about it.

154

00:11:04,950  -->  00:11:07,820
So this court is not available in the resource section.

155

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It is not available.

156

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It's just for demonstration.

157

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So you can test it out and you're ready for that cert.

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Thank you