1 00:00:00,710 --> 00:00:04,390 Industry or Tauriel I want to talk a little bit about classes. 2 00:00:04,590 --> 00:00:09,420 So first let me show you how you can open and close a project. 3 00:00:09,450 --> 00:00:15,840 So in order to open a closed project you just need to double click on it and if you want to actually 4 00:00:16,380 --> 00:00:22,720 close the project just to right click on your project and click on our close project OK. 5 00:00:22,740 --> 00:00:25,310 As you can see this is the close project here. 6 00:00:25,550 --> 00:00:26,140 OK. 7 00:00:26,460 --> 00:00:29,020 So if you want to delete it you can delete. 8 00:00:29,190 --> 00:00:34,260 Right click on your project and then click on it and be sure to check this option here it is. 9 00:00:34,260 --> 00:00:40,470 Project contents on this if you want to completely remove your project from your system. 10 00:00:40,470 --> 00:00:47,670 So first we need actually we need a job a project or the name of what project should be our classes 11 00:00:48,510 --> 00:00:53,390 pre-K the project name should start with a capital letter. 12 00:00:53,450 --> 00:00:54,300 OK. 13 00:00:54,450 --> 00:00:57,440 I use different location and play can finish. 14 00:00:57,800 --> 00:00:58,300 OK. 15 00:00:58,500 --> 00:01:00,730 Now we need to create a Java class. 16 00:01:00,900 --> 00:01:06,870 So in order to create a Java class when it arrives like this as our C for that or this class project 17 00:01:07,610 --> 00:01:12,860 right click on it and actually knew and click on class. 18 00:01:12,870 --> 00:01:13,530 OK. 19 00:01:13,800 --> 00:01:18,230 So for the name of the class I prefer to type in my class. 20 00:01:18,300 --> 00:01:18,980 OK. 21 00:01:19,200 --> 00:01:23,410 We can use any name that you want for the modifiers to public. 22 00:01:23,640 --> 00:01:28,000 And this time check this check box here that says public static void main. 23 00:01:28,140 --> 00:01:31,280 This is actually going to create the main method for us. 24 00:01:31,340 --> 00:01:31,630 OK. 25 00:01:31,630 --> 00:01:33,290 And click can finish. 26 00:01:33,390 --> 00:01:38,180 And as you can see here the main Mfat has been created automatically for us by eclipse. 27 00:01:38,190 --> 00:01:40,580 So this slide here as you can see here this is a comment. 28 00:01:40,590 --> 00:01:41,160 OK. 29 00:01:41,370 --> 00:01:44,360 I teach you about comments later in the section. 30 00:01:44,400 --> 00:01:51,510 So just delete this slide and the first thing that I want to teach you about classes is that classes 31 00:01:51,600 --> 00:01:52,780 are like blueprints. 32 00:01:52,830 --> 00:02:00,810 For example if I want to create a Mercedes-Benz OK I need a blueprint I need a blueprint that actually 33 00:02:00,810 --> 00:02:09,120 can teach me can actually instruct me that include instructions how to create our Mercedes-Benz. 34 00:02:09,180 --> 00:02:09,690 OK. 35 00:02:09,790 --> 00:02:11,510 And classes are the same. 36 00:02:11,520 --> 00:02:18,570 For example if I want to create a Mercedes-Benz I need a blueprint that its name is a Mercedes-Benz 37 00:02:18,690 --> 00:02:22,320 as you can see I can create another class for example. 38 00:02:22,350 --> 00:02:27,110 I can create files and click on File new and class. 39 00:02:27,330 --> 00:02:30,700 Ok for example I want to create a car. 40 00:02:30,740 --> 00:02:32,250 Ok car. 41 00:02:32,660 --> 00:02:33,320 OK. 42 00:02:33,660 --> 00:02:39,020 I click on this checkbox here topics that what man made I click on finish. 43 00:02:39,090 --> 00:02:42,620 OK this is the blueprint for creating a car. 44 00:02:42,840 --> 00:02:45,180 OK this is just a blueprint. 45 00:02:45,180 --> 00:02:47,550 All classes are blueprints. 46 00:02:47,580 --> 00:02:48,290 OK. 47 00:02:48,660 --> 00:02:54,990 So I teach you more about classes later in this course and this is just an introduction to give you 48 00:02:54,990 --> 00:02:57,150 some knowledge about these classes. 49 00:02:57,150 --> 00:02:57,760 OK. 50 00:02:58,060 --> 00:03:07,290 So the next thing that I want to teach you about is that the name of all classes that we create must 51 00:03:07,290 --> 00:03:10,380 be the same as the name of the job or Foyle's. 52 00:03:10,390 --> 00:03:16,110 Here for example as you can see this is the class that we have created. 53 00:03:16,180 --> 00:03:16,860 OK. 54 00:03:17,040 --> 00:03:19,240 In my class that job are fine. 55 00:03:19,320 --> 00:03:20,020 OK. 56 00:03:20,280 --> 00:03:23,370 And does the name of this class is my class. 57 00:03:23,410 --> 00:03:30,930 So as you can see here this is that my class that job or the name of this job is my class too. 58 00:03:30,930 --> 00:03:40,110 So first let me point out that if I for example change the name of this class to my classes as you can 59 00:03:40,110 --> 00:03:42,800 see Eclipse is going to complain. 60 00:03:43,350 --> 00:03:44,700 It's going to show me an error. 61 00:03:44,730 --> 00:03:46,450 So let's see what's this error. 62 00:03:46,560 --> 00:03:48,360 The public type. 63 00:03:48,510 --> 00:03:53,430 My classes must be defined in its own right. 64 00:03:53,430 --> 00:04:01,060 So as you can see here this class my classes is not owned by either my class that Java. 65 00:04:01,440 --> 00:04:05,070 So we need to actually change it back to my class. 66 00:04:05,100 --> 00:04:06,270 OK. 67 00:04:06,630 --> 00:04:08,290 And let's see another example. 68 00:04:08,430 --> 00:04:13,450 As you can see here I'll change the name of this class car to cars. 69 00:04:13,470 --> 00:04:14,120 OK. 70 00:04:14,370 --> 00:04:16,360 As you can see the name of this class is car. 71 00:04:16,380 --> 00:04:16,890 OK. 72 00:04:17,010 --> 00:04:20,080 And the name of the java file here is card too. 73 00:04:20,100 --> 00:04:27,630 So if I change it two cars as you can see it's going to show me an error and it says the public type 74 00:04:27,860 --> 00:04:31,360 cars must be defined in it's all fine. 75 00:04:31,590 --> 00:04:37,250 So as you can see these cars class is not owned by this car that job is fine. 76 00:04:37,560 --> 00:04:48,930 So there are some exceptions to for example Actually if I actually change this class class name here 77 00:04:48,930 --> 00:04:51,500 are two cars and it's gonna show me an error. 78 00:04:51,510 --> 00:04:52,140 OK. 79 00:04:52,260 --> 00:04:54,180 So let's see what the error is. 80 00:04:54,300 --> 00:05:01,590 Again the public high cars must be defined in its own fight as you can see it is the public type. 81 00:05:01,590 --> 00:05:04,500 So let's actually delete this public here. 82 00:05:04,650 --> 00:05:09,760 And as you can see the air is God and it's tested again in my classes. 83 00:05:10,020 --> 00:05:15,760 So if I change into my classes the name of the class to my classes let's delete this public. 84 00:05:16,200 --> 00:05:20,170 And it's going to actually delete the error for me again. 85 00:05:20,460 --> 00:05:23,470 OK so what's going on. 86 00:05:23,470 --> 00:05:28,560 Are all public classes as you can see in every fight in every job. 87 00:05:28,650 --> 00:05:31,660 You can actually create only one public class. 88 00:05:31,830 --> 00:05:32,530 OK. 89 00:05:32,640 --> 00:05:37,670 You can actually create you just one fine one public fight. 90 00:05:37,950 --> 00:05:38,700 OK. 91 00:05:38,970 --> 00:05:46,740 But you can create unlimited classes in your files for example if I change this class to for example 92 00:05:46,740 --> 00:05:56,070 if I put the public back into this class ok and change this card is class 2 car OK and it's going to 93 00:05:56,070 --> 00:05:58,950 actually erase the error for me. 94 00:05:58,950 --> 00:06:03,560 For example if I actually want to put another party class in this fight. 95 00:06:03,750 --> 00:06:05,410 As you can see this is the end of my class. 96 00:06:05,430 --> 00:06:09,760 Ok so I can add another class here public. 97 00:06:10,450 --> 00:06:12,390 OK class. 98 00:06:12,920 --> 00:06:13,690 OK. 99 00:06:13,920 --> 00:06:16,680 So let's this time typing anymore. 100 00:06:16,730 --> 00:06:17,150 OK. 101 00:06:17,160 --> 00:06:18,600 The class of Haleema. 102 00:06:19,530 --> 00:06:23,630 And then open and close the class by using these curly braces. 103 00:06:23,880 --> 00:06:25,950 So as you can see it's going to show me an error again. 104 00:06:25,950 --> 00:06:32,880 So let's see what's this error the public type animal must be defined in its own form. 105 00:06:33,120 --> 00:06:38,850 So as you can see we cannot actually use public time modifier here again. 106 00:06:39,060 --> 00:06:44,800 I'm going to actually tell you more about the public modifier later in this section. 107 00:06:44,820 --> 00:06:53,210 But for now I just want to teach you how these are public you modify your behavior in against classes. 108 00:06:53,220 --> 00:06:53,920 OK. 109 00:06:54,450 --> 00:06:57,670 Now I'm going to teach you and other answers about classes. 110 00:06:57,870 --> 00:07:00,560 So first let's open the mike less that Jarba. 111 00:07:00,840 --> 00:07:05,240 And as you can see here we need to change the class name to my class. 112 00:07:05,400 --> 00:07:07,150 And now the error is caught. 113 00:07:07,430 --> 00:07:14,030 And this closing curly brace as you can see here this is the end of the class declaration. 114 00:07:14,250 --> 00:07:18,930 So as I said before we can create our own limited classes in our Java files. 115 00:07:18,930 --> 00:07:25,390 So for example if I want to create another class named sport I can do it this way. 116 00:07:25,530 --> 00:07:27,370 Class sport. 117 00:07:27,570 --> 00:07:31,790 I need to open and close my class by using these curly braces. 118 00:07:31,860 --> 00:07:39,730 For example if I want to actually create another main method here I can actually type in public case 119 00:07:39,890 --> 00:07:44,960 tatic. 120 00:07:45,120 --> 00:07:50,890 And as you can see we can have our main method for every class that we create. 121 00:07:50,940 --> 00:07:57,930 OK artics OK arguments and then I need to open and close my method by using these curly braces. 122 00:07:57,970 --> 00:08:06,660 So inside this method I want to for example I put some results to the console so I can take in system 123 00:08:07,500 --> 00:08:16,570 that out that princeling this system that out of that Cridland is the job was to actually outwitting 124 00:08:16,600 --> 00:08:19,090 your texts to the council. 125 00:08:19,120 --> 00:08:22,990 OK and I'll teach you more about these classes these methods. 126 00:08:22,990 --> 00:08:32,050 But for now just memorize this and know that this is just a way to actually outputting your texts to 127 00:08:32,050 --> 00:08:33,230 the council. 128 00:08:33,250 --> 00:08:33,830 OK. 129 00:08:33,980 --> 00:08:42,010 So inside the parenthesis I can't say I've been high for sports. 130 00:08:43,160 --> 00:08:47,590 And at the end of my statement I need to put in the semi-colon. 131 00:08:47,790 --> 00:08:51,540 And here again I can actually the type system. 132 00:08:51,670 --> 00:08:54,760 That's how it got trained to learn. 133 00:08:55,350 --> 00:09:08,130 And inside the practices I kept typing Hi from my class as you can see I am typing the name of the class 134 00:09:08,130 --> 00:09:08,860 here. 135 00:09:09,270 --> 00:09:14,260 So let's first run these actually application. 136 00:09:14,340 --> 00:09:23,930 So I just need to Right-Click underclasses project and run as Java application. 137 00:09:24,000 --> 00:09:26,090 So let's see what we have got here. 138 00:09:26,340 --> 00:09:30,930 As you can see these are the classes that we have created earlier. 139 00:09:30,980 --> 00:09:31,570 OK. 140 00:09:31,680 --> 00:09:32,670 This is the card class. 141 00:09:32,670 --> 00:09:36,830 This is the my class class and this and this is the Sports Class. 142 00:09:36,900 --> 00:09:37,440 OK. 143 00:09:37,440 --> 00:09:42,360 So for example if I want to run this sports class I just need to choose this sports class and cricket. 144 00:09:42,360 --> 00:09:43,110 OK. 145 00:09:43,320 --> 00:09:46,160 So as you can see it is going to show me high from sport. 146 00:09:46,230 --> 00:09:46,990 It's going to run. 147 00:09:47,010 --> 00:09:53,070 It's going to actually go inside the sport class and it's going to Randy's main method and inside the 148 00:09:53,160 --> 00:09:59,530 main effect it's going to execute with this statement system that out that principle and high from sports.