#7.5 Kotlin Default Functions with Interoperability with @JvmOverloads Video Lecture | Kotlin Tutorial for Beginners: Learn Kotlin in easy language - Back-End Programming

hi resisting Siddarth and welcome to the
next video of this cortland programming
series now in this video we will learn
about what do we mean by the default
functions in case of Cortland now we
will learn this concept along with the
concept of interoperability so make sure
you have watched my previous videos then
only this video will make sense so first
of all what do we mean by the default
arguments in case of functions now
suppose I have this method named find
volume that takes a parameter of length
breadth and height and simply returns
the integer value of the volume of an
object right now if you notice here here
I have the third parameter as height
equal to 10 now this is actually the
default argument in case of Kotlin so
here even if you do not pass the value
of height equal to something then also
by default the height will have the
value of 10 right so let us take some
example so here from the main method if
I call find volume method and simply
pass 2 & 3 as a parameter that is length
will become 2 breath will become 3 and
height which is by default 10 right so
this will simply return the result of
let's say 60 so in the output we will
have 2 into 3 into 10 equal to 60 right
and now proceeding forward
suppose if I use this method find volume
2 3 and 20 now if you notice here we are
also passing the third parameter so here
length will become 2 breaths will become
3 and in case of height the value will
be overwritten and this 10 will now
become 20 so in the output we are going
to get 2 into 3 into 20 equal to 120
right so by passing some value here we
have simply overridden the default value
that is present here 10 right so here
inside the IntelliJ IDE this is the same
application on top of which we were
working in the previous videos as well
so here inside the cortland file i will
simply create a function so here this
find volume method simply
returns the volume of a particular
object so inside the main method I will
simply use variable result equal to find
volume and simply pass let's say 2/3 as
a parameter now at the end simply print
the value of the result and now here if
you notice here we have to compulsorily
pass the third parameter now what if you
don't have the value of the height to
pass in that third parameter here right
so that is why we have the default
functions in case of Kotlin so here by
default you can give it you can give
this height some value let's say 10 and
now here the error will be rectified and
by passing just two parameters we can
get the volume of the object right here
just because we have the default value
of height as 10 and then simply turn the
code by simply clicking on this icon of
this one and simply and then simply run
the code so here in the output we get 60
right and now here suppose if I pass
let's say 30 now when we are passing the
value of the height then this value of
the height will be overridden and this
10 will be replaced by 30 because the
compiler will give more priority to this
value and now again let us run the code
so here we get 180 in the output so this
is the advantage of using the default
parameters in case of cortland and now
what about the Java file can we call the
default function from our Java file the
answer is yes and no both let's check it
out
now the Java doesn't support the default
function if you are a Java developer
then you must be aware of this we did
not have any concept of default
functions in case of Java so how can we
call the default functions present
inside the Kotlin file from the java
file so for that we have an annotation
of at the rate JVM overloads so this
will simply give rise to the
interoperability of the Java and the
cotton link files so inside the IntelliJ
IDE suppose from the Java
if I try to call the find volume method
by simply using this class name my
custom Kotlin file name my custom
Cortland file name dot find volume and
simply pass let's say for and let's say
7 as a parameter so it will simply show
some error because the required argument
is 3 and we are only passing the two
arguments right just because in Java we
don't have any concept of the default
function so what we can do here is
inside my first dot Katie we can simply
use the annotation right above the find
volume method by using the annotation of
add the rate JVM overloads right so this
will simply make this function
compatible with my Java file now here
the error has gone so now you can simply
pass two parameters and simply get the
result so I will simply use int result
equal to this one and now down the side
I will simply print out the value of
result inside our Java file and now to
run the code you can simply click on
here and then simply run my Java file
dot main so in the output we get the
volume of the object as 280 by simply
passing two parameters and of course you
can pass three parameters as per your
wish let's say 40 height is 40 breadth
and length is 7 and 4 respectively
and now again run the code by clicking
on this icon here so here we get some
other output of 1 1 2 0 as a result so
this was all about the default functions
and in this video itself we also saw how
can we call the default function from a
particular Java file by using the
annotation of add the rate JVM overloads
so see you guys in the next video
thanks for watching this is shrink
Siddharth signing off