WEBVTT 00:01.010 --> 00:01.520 Hi everyone. 00:01.520 --> 00:02.840 Welcome back to this tutorial. 00:02.840 --> 00:07.610 In this tutorial, we will explore the performance of these two methods. 00:07.610 --> 00:09.170 I missed one thing here. 00:09.290 --> 00:10.160 We take a look at this. 00:10.400 --> 00:12.920 In this method I'm not calling the parallel method. 00:13.040 --> 00:18.350 I'm going to make a call to this parallel method and then run this and then check whether the result 00:18.350 --> 00:19.430 are the same. 00:19.460 --> 00:20.270 We take a look at it. 00:20.270 --> 00:21.650 The result are the same. 00:21.650 --> 00:26.360 Now, in this tutorial we are going to focus on calculating the performance. 00:26.360 --> 00:26.840 Right? 00:26.840 --> 00:31.580 So for this purpose, what I'm going to do, I'm going to create a method called. 00:32.580 --> 00:33.360 Public. 00:36.400 --> 00:46.360 Static and then it is going to return a long it is going to be check performance result. 00:46.360 --> 00:49.240 And I would like to call these methods multiple times. 00:49.240 --> 00:54.070 So I want that to be a parameter to this method number of times. 00:55.300 --> 01:04.150 And then this is going to be so let's construct the for loop int I equal to zero I less than number 01:04.150 --> 01:06.940 of times then I plus plus. 01:08.360 --> 01:14.810 So in here we are going to call the some sequential stream and some parallel stream. 01:16.430 --> 01:20.330 And I would like to change this one to camel casing because that is a recommendation for the method 01:20.330 --> 01:21.500 names in Java. 01:21.650 --> 01:25.490 So I'm clicking refactor and then selecting the rename. 01:29.280 --> 01:30.840 Some sequential. 01:32.130 --> 01:35.190 Think, right, what is good. 01:35.190 --> 01:41.190 And then this is going to be some parallel string refactor rename. 01:43.930 --> 01:45.490 Some parallel string. 01:46.030 --> 01:46.570 There we go. 01:47.230 --> 01:49.120 All set in here. 01:49.120 --> 01:53.230 We are going to call some sequential stream and some parallel stream. 01:53.660 --> 01:54.250 Right. 01:54.250 --> 01:58.900 So I don't want to make the call to these two methods inside the for loop. 01:58.900 --> 02:04.310 I want to make the call separately and then take the result how it is performing. 02:04.330 --> 02:05.290 How can we do that? 02:05.290 --> 02:12.460 So for this method, right now I'm just passing the INT number of times I want to pass this method itself 02:12.460 --> 02:13.690 as a parameter to it. 02:13.810 --> 02:14.920 How can we achieve it? 02:15.130 --> 02:16.450 We take a look at this example. 02:16.450 --> 02:20.950 This looks like a supplier, if you remember from the previous tutorials, Supplier is a functional 02:20.950 --> 02:26.080 interface which doesn't accept any input, but it is going to return you a output. 02:26.230 --> 02:31.120 This particular method, these two methods look exactly like a. 02:32.460 --> 02:33.000 The player. 02:33.000 --> 02:38.970 So what I'm going to do in the place of this, I'm going to call, check performance result, and then 02:39.390 --> 02:41.220 I'm going to do parallel stream example. 02:41.220 --> 02:45.030 I'm going to make use of the method reference syntax. 02:45.270 --> 02:51.840 So as soon as I gave that to Colon is giving me the option, I'm going to call the sum sequential stream 02:51.840 --> 02:55.380 and then I'm going to make the call 20 times. 02:56.220 --> 02:57.930 So it is complaining. 02:58.290 --> 02:58.740 What is that? 02:58.740 --> 02:59.310 It is complaining. 02:59.310 --> 03:02.120 The parallel stream right now has only one method. 03:02.130 --> 03:02.490 Right? 03:02.490 --> 03:09.630 I'm going to change this one to supplier and of type integer because the return type is going to be 03:09.630 --> 03:15.450 an integer supplier and all those functional interfaces always refer to the wrapper version of the primitive 03:15.480 --> 03:15.930 type. 03:15.930 --> 03:19.290 So that's the reason why we have to give integer instead of int. 03:19.410 --> 03:21.330 I'm going to name this one as supplier. 03:21.360 --> 03:22.890 Let's import this. 03:23.220 --> 03:24.120 There you go. 03:24.120 --> 03:26.580 So and then the next one, what is the next one? 03:26.610 --> 03:32.790 The next one is going to be some parallel string, right? 03:33.000 --> 03:43.710 Let me give some code comments here is going to be sequential stream result. 03:47.150 --> 03:57.320 Can put this whole thing down and this is going to be a parallel stream result. 04:04.080 --> 04:06.330 So we take a look at it. 04:06.330 --> 04:10.260 This one is calling the sequential stream, and this one is calling the parallel stream. 04:10.260 --> 04:16.050 So in here, what we have to do, we have to call supplier dot get. 04:16.290 --> 04:20.640 So this is going to actually invoke these two methods, right? 04:20.640 --> 04:23.580 The next step is we want to calculate how long did it take? 04:23.580 --> 04:28.290 I'm going to use the system class for this purpose. 04:28.290 --> 04:33.720 It's going to be start time system dot current time milliseconds. 04:35.380 --> 04:46.030 And end time is going to be system dot runtime milliseconds and the return is going to be in time minus 04:46.030 --> 04:47.110 the start time. 04:47.890 --> 04:48.640 There you go. 04:48.670 --> 04:54.490 So this is going to give you the total time it took to execute this method, the number of times, the 04:54.490 --> 04:57.460 number of times value that we are passing is that 20 times. 04:57.460 --> 05:04.000 So this some sequential stream is going to be called 20 times and some parallel stream is going to be 05:04.000 --> 05:05.260 called 20 times. 05:05.260 --> 05:08.830 And then this is going to give you the number of. 05:09.850 --> 05:14.140 Then how many milliseconds that it took in order to calculate the output for you. 05:14.590 --> 05:14.890 Right. 05:14.890 --> 05:16.930 I'm going to run this example. 05:17.350 --> 05:18.490 We run this example. 05:18.490 --> 05:20.580 It took like this one. 05:20.590 --> 05:27.100 The sequential stream result took 15 milliseconds, but the parallel stream just took seven milliseconds. 05:27.100 --> 05:28.810 So what happens behind the scenes? 05:28.810 --> 05:30.050 What happens under the hood? 05:30.070 --> 05:31.750 How many threads got created? 05:31.780 --> 05:34.870 Those are the interesting things which might be running in your mind. 05:34.900 --> 05:38.080 I'm going to cover those in the next tutorial. 05:38.110 --> 05:40.280 With this, we came to the end of this tutorial. 05:40.300 --> 05:41.470 Thank you for watching.