WEBVTT 00:00.080 --> 00:00.650 Hi everyone. 00:00.650 --> 00:01.130 Welcome back. 00:01.130 --> 00:05.240 In this lecture we are going to be learning about a new concept named Unnamed Module. 00:05.240 --> 00:08.810 So unnamed module is how pretty much most of the projects work. 00:08.810 --> 00:13.190 Let's say if you are already building on some kind of, uh, Java application, it could be a spring 00:13.190 --> 00:15.650 boot application or any other kind of framework. 00:15.680 --> 00:23.420 You are executing your code in your modern Java platform, maybe a Java 11 or Java 17, whatever that 00:23.420 --> 00:24.050 might be. 00:24.080 --> 00:27.260 You are running your code as an unnamed module. 00:27.380 --> 00:32.660 What that means is that let's say you are executing your code in the modern Java platform, and if you 00:32.690 --> 00:38.360 are not providing any module descriptor file like a module-info.java file, that means your code is 00:38.390 --> 00:41.120 being executed as a unnamed module. 00:41.120 --> 00:43.760 So in this lecture we'll go ahead and explore that one. 00:43.760 --> 00:48.380 For this specific lecture, we are going to be working on the module four module. 00:48.380 --> 00:51.140 So in this case this is a very simple module. 00:51.140 --> 00:53.960 And if you take a look at it it has a main class and the main class. 00:53.960 --> 00:57.350 What it does is that it's going to print you the module name. 00:57.380 --> 00:57.800 Okay. 00:57.830 --> 01:02.270 Pretty much every module that you have worked on so far will have this main class. 01:02.270 --> 01:06.930 There is a reason why I have that class will be leveraging that in this specific lecture. 01:06.930 --> 01:12.420 So now what I'm going to do here is that so for this specific class we don't have any module file. 01:12.450 --> 01:12.960 Right. 01:12.960 --> 01:18.360 But when you execute this main class it's going to have access to this module name. 01:18.360 --> 01:20.550 And then we are going to see what is a value. 01:20.550 --> 01:21.750 It is going to print. 01:22.080 --> 01:27.330 So to start with what I'm going to do I'm going to open the Gradle section over here and then go to 01:27.360 --> 01:33.600 the module for in the module for what we will do, we'll go ahead and execute the build task. 01:33.600 --> 01:35.580 So what this build task is going to do. 01:35.610 --> 01:38.370 This is going to take care of building the project for you. 01:38.370 --> 01:41.790 And then it is going to place the jar file in the libs directory. 01:41.790 --> 01:44.700 So in this case what we will do I have the terminal open here. 01:44.700 --> 01:47.190 So we are going to be navigating to the module four. 01:47.220 --> 01:50.940 So CD modules module four. 01:50.970 --> 01:51.690 There you go. 01:51.690 --> 01:52.560 And then do a ls. 01:52.560 --> 01:55.350 So this is where the build directory and everything is here. 01:55.350 --> 01:58.590 So now what I'm going to do I'm going to execute the jar file. 01:58.590 --> 02:03.240 And while I'm executing the jar file I'm going to execute this main class okay. 02:03.270 --> 02:06.210 So let's go ahead and do the execution of this one. 02:06.240 --> 02:09.130 In this case Java hyphen hyphen Classpaths. 02:09.130 --> 02:14.440 So this is how we normally launch a Jar file, or execute a class that's inside a Jar file. 02:14.440 --> 02:18.730 And then you provide a class path, and then you provide the path where the jar file is present. 02:18.730 --> 02:22.210 In this case it's going to be build slash libs. 02:22.210 --> 02:25.150 And then we provide the module for that jar file. 02:25.150 --> 02:27.370 And then we provide the class name. 02:27.370 --> 02:33.580 So in this case the class is going to be com dot module four dot main. 02:33.580 --> 02:38.530 So when you execute this code what we are doing here is that we are going to statically print this value. 02:38.530 --> 02:43.300 But it's going to give you a module name that gets created automatically for you. 02:43.330 --> 02:43.840 Right. 02:43.870 --> 02:49.750 If you press enter here you see right there is something called an unnamed module. 02:49.750 --> 02:57.130 So this particular module, when you execute in a modern JDK platform, anything after Java nine, those 02:57.130 --> 03:03.430 classes or applications are still run as a module, but in this case it's called an unnamed module. 03:03.430 --> 03:10.510 This is specifically done for us, just to make sure the portability of executing the Non-modular code 03:10.510 --> 03:13.080 in the modular Java platform. 03:13.080 --> 03:17.040 So that's the main purpose of introducing this unnamed module concept. 03:17.280 --> 03:20.460 In addition to the classpath, we have another concept called module path. 03:20.460 --> 03:22.800 So how do we execute a code in a module path. 03:22.800 --> 03:26.430 So all you got to do is we're going to use a somewhat similar command. 03:26.430 --> 03:29.940 But in here we're going to change a few things. 03:29.940 --> 03:35.700 So in this case the very first thing is I'm going to provide something called a module path okay. 03:35.730 --> 03:37.200 So let's go ahead and create the module path. 03:37.200 --> 03:39.930 And then you provide the module after this one. 03:39.930 --> 03:41.250 So we have the module path. 03:41.250 --> 03:45.660 And this is a directory where all the modules are present for the specific application. 03:45.660 --> 03:49.290 And then you provide a module name by using the hyphen m flag. 03:49.290 --> 03:52.170 And then the module name is going to be module four. 03:52.170 --> 03:55.560 And then slash comm dot module four dot main. 03:55.560 --> 03:58.200 So if you execute this class you're going to see a different result. 03:58.200 --> 04:00.000 Press enter over here you see right. 04:00.030 --> 04:04.860 So in this case it was able to automatically add a name for the specific module. 04:04.860 --> 04:07.860 So this concept is called automatic modules. 04:07.890 --> 04:10.830 Unnamed module and automatic module are specifically used. 04:10.830 --> 04:17.560 If you are going to be running a non-modular code in a module path or in a modern Java platform. 04:17.560 --> 04:18.640 So this is a concept. 04:18.640 --> 04:24.370 Any time you are, you may be running your applications already in a JDK 17 or JDK 21, which is the 04:24.370 --> 04:28.750 latest if you're wondering how this code is getting run in that environment. 04:28.750 --> 04:34.270 If you don't have any module file in it, if you're just using the classpath, then those code are still 04:34.300 --> 04:37.210 being bundled and run as an unnamed module. 04:37.210 --> 04:42.280 When you're executing your code in an unnamed module, what happens is that it's going to have visibility 04:42.280 --> 04:44.350 to all the platform modules. 04:44.350 --> 04:49.450 In this case, this unnamed module will have access to all the modules that we have over here. 04:49.450 --> 04:54.430 So whatever you see here, all these modules will be visible to that unnamed module. 04:54.460 --> 05:00.070 I hope you all have a pretty good idea about how the unnamed module works, and how the code that we 05:00.070 --> 05:04.360 write today without the module file gets executed in the modern Java platform. 05:04.360 --> 05:09.700 If you are running your code without the module file, you can still continue to do it without any issues. 05:09.700 --> 05:11.350 But this is for your understanding. 05:11.350 --> 05:16.900 Even though we are not providing any module file, your code is still being bundled and executed as 05:16.900 --> 05:18.550 an unnamed module. 05:18.580 --> 05:19.930 This marks the end of this lecture. 05:19.930 --> 05:21.070 Thank you for watching.