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Okay, so first things first, we're gonna
need to set our language level to eight.

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By default,
probably things are set to seven.

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Most editors keep themselves pinned to
a current language level just to make sure

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that others using your code know
what they can and can't use.

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So, let's check it out.

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So if we go File > Project Structure,
and here under Project,

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you'll see the project language level.

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And just like I thought,
it was limited to seven.

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So let's go ahead and
let's flip that to eight.

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And we'll click OK.

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You'll notice now that
this turned gray here.

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Then what this is saying,

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is it's saying that the new comparator
book can be replaced with a lambda.

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Let's open that up just a little bit more.

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It says, this inspection
reports all anonymous classes,

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which this was, which can be
replaced with lambda expressions.

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Okay, cool, so let's just do that.

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Let's leave this reference here, for
what was there, and we will dupe this.

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And let's make a new method that
will accomplish the same thing.

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Like Def Leppard said, let's pour some
sugar on it, syntactic sugar, that is.

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So I'm gonna show you
a long-form class first.

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So we'll call this usingLambdasInLongForm.

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Okay, so what we're gonna replace is we're
gonna get rid of this comparator that we

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have going on here.

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So I'm gonna get rid of this.

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So the first thing that we wanna do
here is put a pair of parentheses, and

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inside of these parentheses is
where we define our parameters.

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So the parameters that we
know from before that were

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being requested was there was this book.

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There's a book and it was called b1,
it doesn't have to be,

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it can be called whatever.

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And b2.
In order to say that this is a lambda,

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what we want to do is we
want to make a little arrow.

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You do a minus and
then a greater-than sign.

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See how it looks like an arrow?

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And then we can use the curly braces,
just like we did before, and

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we can do the same code that
we had before too as well.

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So we'll just copy this,
and paste that here.

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Cool, so let's go ahead and we'll change
this to say, usingLambdasInLongForm.

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We'll save it and we'll run it.

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Okay, cool, it's still working.

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That's definitely some space
savings line-wise, right?

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We didn't have to declare the new type,
the comparator book,

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it just kind of figured that out.

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And we also didn't have to declare
the method name which was compared,

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it also figured that out right?

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It doesn't say anything about
the method name being compare or

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that it's the comparator interface.

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But we can make this even more concise.

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So, if you've come across some of these
before you were probably wondering what

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the heck was going on,
I know I did the first time I saw them.

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So let's go ahead and
let's dupe this method into a short form.

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So, we'll say public static
in ShortForm this time.

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Okay, so
the compiler can actually figure stuff out

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well enough that you don't
even need to declare types.

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So, let's get rid of those, right.

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So, it knows that it's
expecting two books.

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So, let's get rid of that.

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Okay, cool.

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Now, if you have a single line method,
you actually don't need the curly braces.

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Let's go ahead and get rid of those.

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You put this all up on the next line.

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When you only have a one-liner you
actually don't even need the return

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keyword, it knows what's
expected to be returned.

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So, let's get rid of the keyword.

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Return.
And let's bring this up a line, cool.

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So that one-liner is called
an expression type body.

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This creates a function
that accepts two books, and

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returns the value from
this statement here.

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Let's make sure that we change this
to say usingLambdasInShortForm.

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All right, so let's run it.

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Cool, it still works.

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Pretty succinct, right?

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Now, like I mentioned,

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these opened up a new style of programming
known as functional programming.

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We're not gonna delve to deep here, we'll
cover that fully later in another course.

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But, let's get a quick little sneak peak.

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So, the collections framework really
benefits from functional programming.

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And one super cool thing that got added
is the forEach method on collections.

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It takes a consumer, which is a newly
introduced functional interface,

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remember that's the new name for
a single abstract methods.

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Now, a consumer expects a parameter
that takes one of its container's types.

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So, let's replace this forEach loop.

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So, we'll do books.forEach,
which is the new method.

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And, it takes a consumer,
so the consumer is book.

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And for each one of those books,
we're just gonna print out.

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Cool, so now if I run it, still working.

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All right, are you ready for
even more succinctness?

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When you just have one parameter,
you don't even need the parentheses, so

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let's get rid of this
cuz there's only one.

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So it's saying for each book, run this.

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So since we're here, I wanna show you one
more thing that you might come across that

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might look a little bit foreign, and
that's called method references.

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Let's take a look in the next video.