WEBVTT

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Hi everyone.

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Welcome back to this tutorial.

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In this tutorial, we will explore how parallel stream works behind the scenes.

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Parallel Stream uses the fork join framework under the hood to process the streams.

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Parallelly and the fork.

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Join framework got introduced as part of Java seven.

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Fork join creates multiple threads for you, but the question here is how many threads that gets created.

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The number of threads that gets created is equal to the number of processors that are available in the

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machine.

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The main reason for this way of spawning the threads is the advancement of technology in the world today.

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Today, even smartphones that you have in your hand has multiple processors.

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The idea is to use those resources available to perform the concurrent processing.

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Let's go ahead and check how many processors are available in this machine.

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I'm going to go to the IntelliJ and then what I'm going to do, I'm going to do a Sis out and run time

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dot get runtime dot available processors.

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So this is going to give you how many processors are available in this machine run.

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This is going to give you the value here as eight So this machine has eight processors.

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So as soon as this parallel method call happened and then because the terminal operation is the one

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which is going to start the whole pipeline as soon as the some method is called and it checks, okay.

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Is it a parallel stream or a sequential stream?

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If it is a parallel stream, this is going to split the data into multiple parts and process them concurrently

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and it is going to accumulate the result and give you the result as a output.

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I would like to show you what happens behind the scenes using using the presentation here.

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So if you go here, this machine has eight processors.

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That's what we checked here.

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So sequential stream, what it is going to do, it is going to perform the complete summation operation

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using one processor.

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It is not going to leverage the multiple processors that you have in your machine.

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But in the case of parallel stream, this is going to split the whole data source into multiple parts

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and then assign each part to a processor.

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And this processor is going to take care of performing the summation for you.

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Parallelly And towards the end it is going to sum all the result and give you the result as a output.

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So this is all about what happens behind the scenes when you call the parallel stream method.

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With this.

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We came to the end of this tutorial.

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Thank you for watching.