1 00:00:00,480 --> 00:00:05,160 Hi everyone in this theater real I'm going to touch about objects in Java. 2 00:00:05,160 --> 00:00:05,780 OK. 3 00:00:06,000 --> 00:00:13,180 So first of all we need to create a project so click on find new and then click on Java project. 4 00:00:13,200 --> 00:00:14,410 OK. 5 00:00:15,180 --> 00:00:20,620 And for the project name just type in here objects and click unfinished. 6 00:00:21,000 --> 00:00:23,910 So as you can see here our project is now created. 7 00:00:24,030 --> 00:00:26,530 So we need a class for our project. 8 00:00:26,580 --> 00:00:33,270 So just click on this as our See folder or you can click on these objects project click on File New 9 00:00:33,360 --> 00:00:34,490 and then click on a class. 10 00:00:34,500 --> 00:00:35,750 OK. 11 00:00:36,030 --> 00:00:41,670 So remember that for every project that you create in Java you'll need a main class. 12 00:00:41,670 --> 00:00:46,900 OK so now we want to actually create a main class for our project. 13 00:00:47,080 --> 00:00:54,960 Just type in here Main and for the package name just type in our reverse domain here come that your 14 00:00:54,960 --> 00:00:59,270 name dot project name objects. 15 00:00:59,780 --> 00:01:00,580 OK. 16 00:01:00,900 --> 00:01:03,340 And for the modifiers choose public. 17 00:01:03,540 --> 00:01:08,870 And here make sure that you check this check box here that says public static void main method. 18 00:01:08,890 --> 00:01:09,340 OK. 19 00:01:09,510 --> 00:01:13,920 This is going to be the starting point for actually running our Java code. 20 00:01:13,950 --> 00:01:14,430 OK. 21 00:01:14,490 --> 00:01:18,130 Otherwise our coats won't be executed at all. 22 00:01:18,240 --> 00:01:23,610 OK so this method is very important but because this class that we are actually creating now is the 23 00:01:23,610 --> 00:01:25,640 main class of our project. 24 00:01:25,800 --> 00:01:28,910 This method is required for this class. 25 00:01:28,920 --> 00:01:29,810 OK. 26 00:01:29,940 --> 00:01:31,450 So just click on finish. 27 00:01:32,130 --> 00:01:36,680 And as you can see here our class is now created and this is our main method. 28 00:01:36,690 --> 00:01:37,380 Okay. 29 00:01:37,840 --> 00:01:40,260 And here let me actually delete this comment here. 30 00:01:40,410 --> 00:01:46,690 And in order to make this editor area a much wider DoubleClick undismayed that you have here. 31 00:01:46,890 --> 00:01:51,270 So as you can see here are a little area is now much wider. 32 00:01:51,270 --> 00:01:55,370 So as I said earlier in this tutorial I want to talk about objects. 33 00:01:55,500 --> 00:01:57,340 OK so what are objects. 34 00:01:57,390 --> 00:02:03,000 First of all let me point out that Java is an object oriented programming language. 35 00:02:03,030 --> 00:02:05,690 OK so what is an object. 36 00:02:05,760 --> 00:02:09,430 What do you see when you look at the world around you. 37 00:02:09,660 --> 00:02:12,590 You see objects right in Java. 38 00:02:12,900 --> 00:02:15,190 We've got the same objects too. 39 00:02:15,420 --> 00:02:18,750 So so what is the definition of an object. 40 00:02:18,750 --> 00:02:22,610 Objects are a representation of things. 41 00:02:22,920 --> 00:02:25,300 Let's look at the world around us. 42 00:02:25,350 --> 00:02:27,120 You see objects everywhere. 43 00:02:27,330 --> 00:02:29,810 For example animals are objects. 44 00:02:29,820 --> 00:02:30,630 OK. 45 00:02:30,790 --> 00:02:34,910 A lion is an object a person is an object. 46 00:02:34,980 --> 00:02:36,740 A pen is an object. 47 00:02:36,780 --> 00:02:40,120 OK your desk is an object. 48 00:02:40,260 --> 00:02:42,480 And lots of other examples. 49 00:02:42,480 --> 00:02:50,040 So when you for example look at a lion you can write a tell me the characteristics and behaviors of 50 00:02:50,040 --> 00:02:50,680 this lion. 51 00:02:50,700 --> 00:02:51,430 OK. 52 00:02:51,600 --> 00:02:56,540 For example the characteristics of a lion are a lion has powerful legs. 53 00:02:56,550 --> 00:02:56,960 OK. 54 00:02:56,970 --> 00:03:01,220 The second characteristic is a lion has a strong jaw. 55 00:03:01,350 --> 00:03:04,290 The first characteristic is a lion is brave. 56 00:03:04,400 --> 00:03:07,910 OK so now let's talk about the behaviors of a lion. 57 00:03:08,100 --> 00:03:08,590 OK. 58 00:03:08,610 --> 00:03:17,370 For example the behaviors of a lion are a lion spends much of his time resting and is in active for 59 00:03:17,370 --> 00:03:19,230 about 20 hours per day. 60 00:03:19,350 --> 00:03:19,900 OK. 61 00:03:19,920 --> 00:03:26,370 That such behavior is an attempt to catch the victim with a fast rush. 62 00:03:26,400 --> 00:03:33,570 The first behavior is a lawyer and takes advantage of the factors that reduce visibility OK. 63 00:03:33,810 --> 00:03:37,060 So how we can relate this example to Java. 64 00:03:37,260 --> 00:03:40,520 So first we need to create a Java class called the law. 65 00:03:40,530 --> 00:03:40,950 OK. 66 00:03:40,980 --> 00:03:43,380 So now let's actually create a Java class. 67 00:03:43,920 --> 00:03:45,910 So click on this package here. 68 00:03:46,200 --> 00:03:46,790 OK. 69 00:03:47,070 --> 00:03:50,900 And then click on find new and then click on class. 70 00:03:50,930 --> 00:03:56,370 So for the name of the class just type in here Lorient with the capital L.. 71 00:03:56,630 --> 00:03:57,150 OK. 72 00:03:57,240 --> 00:04:03,330 And here for the package as you can see it's going to put this class inside this package. 73 00:04:03,330 --> 00:04:03,900 OK. 74 00:04:04,080 --> 00:04:09,960 So that's why I actually clicked on this package and then I started to create a class. 75 00:04:09,990 --> 00:04:10,320 OK. 76 00:04:10,320 --> 00:04:11,580 So this is really important. 77 00:04:11,700 --> 00:04:14,300 So this class is going to be inside this package. 78 00:04:14,310 --> 00:04:15,090 OK. 79 00:04:15,510 --> 00:04:19,110 And for the modifiers to publish and then click Finish. 80 00:04:19,110 --> 00:04:22,780 Our class is now created the name of our class is a lion. 81 00:04:22,820 --> 00:04:25,170 OK so what is the class. 82 00:04:25,380 --> 00:04:30,450 As I said earlier our class is a blueprint for creating objects. 83 00:04:30,450 --> 00:04:31,040 OK. 84 00:04:31,230 --> 00:04:34,700 Without a blueprint you cannot create an object. 85 00:04:34,860 --> 00:04:38,200 So suppose that you want to create a car. 86 00:04:38,430 --> 00:04:42,360 What would be the first step in order to actually create a car. 87 00:04:42,510 --> 00:04:47,740 First of all you need a blueprint that shows you exactly how you can create a car. 88 00:04:47,970 --> 00:04:48,540 OK. 89 00:04:48,630 --> 00:04:54,900 So for example this is a blueprint for creating a car or create this blueprint is going to actually 90 00:04:54,900 --> 00:04:57,860 show me exactly how I can create a car. 91 00:04:57,930 --> 00:04:58,470 OK. 92 00:04:58,590 --> 00:05:04,520 So in Java programming reach the blueprint is the class that we create in our projects. 93 00:05:04,530 --> 00:05:04,950 OK. 94 00:05:04,980 --> 00:05:11,870 For example this class is going to be our blueprint in order to show us exactly how I can create life 95 00:05:11,870 --> 00:05:13,000 and objects. 96 00:05:13,020 --> 00:05:13,590 OK. 97 00:05:13,710 --> 00:05:18,730 So as you can see here there are no instructions inside this class. 98 00:05:18,750 --> 00:05:24,870 So now I want to actually put some instructions inside this class in order to show me how I can create 99 00:05:24,940 --> 00:05:26,130 loyal objects. 100 00:05:26,130 --> 00:05:29,970 OK so now let's go back to our car example. 101 00:05:30,090 --> 00:05:35,570 First of all you need a blueprint in order to show you exactly how you can create a car. 102 00:05:35,700 --> 00:05:36,290 OK. 103 00:05:36,420 --> 00:05:40,670 So a car has some characteristics and behaviors. 104 00:05:40,800 --> 00:05:43,170 So what are the characteristics of a car. 105 00:05:43,380 --> 00:05:43,970 OK. 106 00:05:44,130 --> 00:05:49,170 The characteristics of a car are first of all a car has four wheels. 107 00:05:49,170 --> 00:05:57,930 Second of all a car has the braking system and Firstly a car has a steering system OK and a car has 108 00:05:58,020 --> 00:05:59,680 some behaviors too. 109 00:05:59,850 --> 00:06:02,150 So what are the behaviors of a car. 110 00:06:02,280 --> 00:06:04,510 Firstly a car can move. 111 00:06:04,710 --> 00:06:07,100 And secondly a car can break. 112 00:06:07,260 --> 00:06:13,210 OK so now let's go back to our code because I want to show you how you can create objects out of classes. 113 00:06:13,230 --> 00:06:13,560 OK. 114 00:06:13,590 --> 00:06:17,160 So now I want to give some characteristics to my life and class. 115 00:06:17,160 --> 00:06:17,780 OK. 116 00:06:18,000 --> 00:06:21,610 So first of all a lion can run very fast. 117 00:06:21,660 --> 00:06:27,220 So now you want to actually create a variable in order to store the amount of speed that allow you and 118 00:06:27,250 --> 00:06:28,540 can run OK. 119 00:06:29,010 --> 00:06:29,740 OK. 120 00:06:30,120 --> 00:06:36,450 The name of my variable is speed and that I can assign a value to my variable for example 100. 121 00:06:36,590 --> 00:06:37,310 OK. 122 00:06:37,350 --> 00:06:40,970 And then at the end of my statement I need to put in a semicolon. 123 00:06:41,070 --> 00:06:48,150 So as you can see here this variable here is the characteristic of my line class. 124 00:06:48,250 --> 00:06:56,070 Ok this argument here is going to show us what would be the amount of speed of our and objects. 125 00:06:56,070 --> 00:07:01,510 OK so now I want to actually create an object from this class. 126 00:07:01,530 --> 00:07:03,260 So how can I do that. 127 00:07:03,270 --> 00:07:07,770 So first of all let me point out that always save your classes. 128 00:07:07,890 --> 00:07:15,480 So if you are using too match or six just press on comment keep Plus the s key on your keyboard in order 129 00:07:15,480 --> 00:07:16,570 to save your class. 130 00:07:16,740 --> 00:07:23,820 But if you are using a Windows machine press on control key plus the key on your keyboard in order to 131 00:07:23,820 --> 00:07:24,560 save your class. 132 00:07:24,570 --> 00:07:25,200 OK. 133 00:07:25,500 --> 00:07:31,140 So as you can see here there is a Lego Star here beside my class name. 134 00:07:31,170 --> 00:07:31,750 OK. 135 00:07:32,010 --> 00:07:37,800 So now if I actually save my project as you can see that little star is now gone. 136 00:07:37,910 --> 00:07:38,450 OK. 137 00:07:38,550 --> 00:07:42,680 This means that my class is now successfully saved. 138 00:07:42,690 --> 00:07:43,430 OK. 139 00:07:43,830 --> 00:07:50,220 So go back inside the main class and here you want to create an object from the slide in class. 140 00:07:50,230 --> 00:07:52,090 Or you want to create a like an object. 141 00:07:52,110 --> 00:07:52,590 OK. 142 00:07:52,680 --> 00:07:56,440 So in order to create an object from a class. 143 00:07:56,610 --> 00:07:59,540 First of all you're literally first to the name of that class. 144 00:07:59,550 --> 00:08:03,050 So the name of my class is Lion as you can see here. 145 00:08:03,060 --> 00:08:04,010 OK. 146 00:08:04,350 --> 00:08:07,500 So so here I just need to type in line. 147 00:08:07,980 --> 00:08:11,640 So as you can see here the name of my class is lion. 148 00:08:11,910 --> 00:08:12,500 OK. 149 00:08:12,600 --> 00:08:16,650 And here I want to give a name to my lion object. 150 00:08:16,650 --> 00:08:25,380 So the name of my your object is my lion and then I want to instantiate my lion object. 151 00:08:25,410 --> 00:08:26,000 OK. 152 00:08:26,100 --> 00:08:32,870 I put an assignment operator here and then I'll use the new keyboard here. 153 00:08:33,030 --> 00:08:34,430 OK this is very important. 154 00:08:34,500 --> 00:08:41,670 Whenever that you want to create an object from a class you need to put this new keyboard after the 155 00:08:41,670 --> 00:08:43,350 assignment operator OK. 156 00:08:43,500 --> 00:08:49,500 This new key word means that we want to create a new object from that specific class. 157 00:08:49,500 --> 00:08:54,170 In this case we want to create a new object from this class. 158 00:08:54,210 --> 00:08:54,900 OK. 159 00:08:55,060 --> 00:09:02,790 So new and again I need to refer to the name of my class line and then I put a pair of round brackets 160 00:09:03,090 --> 00:09:04,370 after my class name. 161 00:09:04,890 --> 00:09:08,070 And then at the end of my statement I need to put in a semi-colon. 162 00:09:08,070 --> 00:09:08,680 OK. 163 00:09:09,000 --> 00:09:12,740 So as you can see here our object is now created. 164 00:09:12,860 --> 00:09:13,410 OK. 165 00:09:13,650 --> 00:09:16,410 So now that our object is created. 166 00:09:16,410 --> 00:09:19,200 So it's going to be saved inside the memory. 167 00:09:19,200 --> 00:09:19,860 OK. 168 00:09:19,980 --> 00:09:25,370 So in order to actually show you how this object is going to be saved inside the memory. 169 00:09:25,440 --> 00:09:29,630 So first of all let me show you the address of this object inside the memory. 170 00:09:29,670 --> 00:09:37,910 So I just need to type in here system that's out that print line and then inside the practices. 171 00:09:38,010 --> 00:09:40,500 I just need to refer to the name of my object. 172 00:09:40,800 --> 00:09:44,980 And then at the end of my statement I need to put in a semi-colon OK. 173 00:09:45,420 --> 00:09:52,470 So now if you run my project as you can see this is the address of our object inside the memory. 174 00:09:52,500 --> 00:09:56,910 Ok you don't need to know that where this object is actually saved. 175 00:09:56,940 --> 00:10:03,580 You just need to know that your object is created and it is stored somewhere inside the memory OK.