1 00:00:00,150 --> 00:00:07,620 So these two String instances here now actually to hold the address of two different objects in memory. 2 00:00:07,620 --> 00:00:08,470 OK. 3 00:00:08,970 --> 00:00:10,530 So these are actually pointers. 4 00:00:10,530 --> 00:00:16,050 This my first name here is actually a pointer to this object in say the memory. 5 00:00:16,140 --> 00:00:20,800 Ok this instance doesn't hold this object within it. 6 00:00:21,060 --> 00:00:26,160 This instance only holds the address of this object inside the memory. 7 00:00:26,160 --> 00:00:26,710 OK. 8 00:00:26,910 --> 00:00:28,970 So hopefully that makes sense now. 9 00:00:29,250 --> 00:00:34,260 So now let me actually comment out these lines of code here and I want to actually show you another 10 00:00:34,260 --> 00:00:38,440 way of creating String objects in Java. 11 00:00:38,460 --> 00:00:38,910 OK. 12 00:00:39,000 --> 00:00:47,270 As you saw above that when we tried to assign the same String object to two different literals compiler 13 00:00:47,300 --> 00:00:54,060 only created one object and made both of the literals to point the same object. 14 00:00:54,090 --> 00:01:00,820 OK so now I want to actually show you how we can actually create String objects in an other way. 15 00:01:01,190 --> 00:01:07,790 And in that case the compiler would create two different objects in memory having the same text. 16 00:01:07,790 --> 00:01:13,420 So for example First we need to actually refer to the name of our class Stream. 17 00:01:14,030 --> 00:01:21,570 And the name of our object is for example C Our object one. 18 00:01:21,920 --> 00:01:25,220 And then I need to put in an assignment operator here. 19 00:01:25,340 --> 00:01:29,370 And then I need to put in this key here new. 20 00:01:29,480 --> 00:01:32,490 And then again I need to refer to the name of constraint. 21 00:01:32,540 --> 00:01:33,300 OK. 22 00:01:33,590 --> 00:01:37,360 And then I need to put in a semicolon at the end of my statement. 23 00:01:37,430 --> 00:01:43,170 So as you can see here I created a string object called C R object 1. 24 00:01:43,280 --> 00:01:43,830 OK. 25 00:01:44,000 --> 00:01:51,020 As you can see I can actually assign value to this as an object one inside the practice's here. 26 00:01:51,080 --> 00:01:51,570 OK. 27 00:01:51,710 --> 00:01:59,230 So this is a constructor in string class that allows us to actually assign value to our string instances. 28 00:01:59,240 --> 00:02:02,150 OK so I can actually just type in here. 29 00:02:02,570 --> 00:02:04,800 Hello world. 30 00:02:05,170 --> 00:02:06,230 OK. 31 00:02:06,950 --> 00:02:12,400 And now as you can see I created an object called Hello world. 32 00:02:12,520 --> 00:02:17,170 OK so now I can actually create another object here. 33 00:02:17,210 --> 00:02:21,340 I just need to refer to the name of the class 3. 34 00:02:21,940 --> 00:02:22,740 OK. 35 00:02:22,820 --> 00:02:28,760 And the name of the object is Esti are object to. 36 00:02:28,840 --> 00:02:29,610 OK. 37 00:02:29,630 --> 00:02:35,320 And then I need to put in an assignment operator here and then I put in this key word here new. 38 00:02:35,510 --> 00:02:42,170 And then I again refer to the name of the String class and then I put in Apprentice's here and then 39 00:02:42,200 --> 00:02:45,100 I put in a semicolon at the end of my statement. 40 00:02:45,200 --> 00:02:52,700 And now I can actually assign a value to our it's art object to by using a constructor that is inside 41 00:02:52,700 --> 00:02:53,570 the as three in class. 42 00:02:53,570 --> 00:03:00,620 OK so remember that a string class is a predefined class for us those constructors are pre-defined for 43 00:03:00,620 --> 00:03:01,890 us and we can use them. 44 00:03:02,060 --> 00:03:07,400 So inside the prentices I just need to put in two double quotes and then instead of double quotes again 45 00:03:07,430 --> 00:03:10,120 I can just type in Hello world. 46 00:03:10,580 --> 00:03:18,520 So as you can see here I created two different strange instances with the same value but the this time 47 00:03:18,620 --> 00:03:23,320 the address of these two objects is going to be completely different inside the memory. 48 00:03:23,330 --> 00:03:23,770 OK. 49 00:03:23,810 --> 00:03:31,160 So this object is going to be saved inside the memory in one place and in and this object is going to 50 00:03:31,160 --> 00:03:34,510 be actually saved inside the memory in another place. 51 00:03:34,530 --> 00:03:38,910 OK that's it that's how you can actually create a string object in Java. 52 00:03:38,930 --> 00:03:44,750 And now I want to actually talk more about these string objects in order to make this concept more meaningful 53 00:03:44,750 --> 00:03:45,170 for you. 54 00:03:45,200 --> 00:03:52,130 OK so now if I want to output the value of these string instances to the console I just need to type 55 00:03:52,130 --> 00:03:59,300 in here system that out that princeling and that inside the prentices I can just refer to the name of 56 00:03:59,300 --> 00:04:02,400 the object as the object one. 57 00:04:02,630 --> 00:04:05,710 And then I need to put in a semi-colon at the end of my statement. 58 00:04:05,720 --> 00:04:11,990 So now if I had on my project as you can see this value is output to the counselor OK or I can actually 59 00:04:12,170 --> 00:04:16,510 output the value of this SDR object to the console. 60 00:04:16,520 --> 00:04:22,310 So I just need to type in here sees them that out that print to learn and then inside the parenthesis 61 00:04:22,340 --> 00:04:24,770 I can just refer to the name of my object. 62 00:04:24,770 --> 00:04:25,340 OK. 63 00:04:25,610 --> 00:04:30,860 As the object to and that I need to put in a semicolon at the end of my statement. 64 00:04:31,070 --> 00:04:36,540 And now if I start my project as you can see this value again is output to the console OK. 65 00:04:36,860 --> 00:04:44,020 And remember that these two objects are actually stored in memory in two different places. 66 00:04:44,030 --> 00:04:50,460 OK because we created these string objects by using these new key word here. 67 00:04:50,510 --> 00:04:51,250 OK. 68 00:04:51,620 --> 00:04:52,980 So this is really important. 69 00:04:53,000 --> 00:04:58,460 You can actually create String objects by just using these string literals or you can actually create 70 00:04:58,670 --> 00:05:02,130 string objects by using this new keyboard here. 71 00:05:02,210 --> 00:05:02,970 OK. 72 00:05:03,350 --> 00:05:07,970 So to recap strings are a sequence of characters. 73 00:05:07,970 --> 00:05:08,680 OK. 74 00:05:08,960 --> 00:05:18,410 In Java programming language strings are objects and the Java platform provides string class to create 75 00:05:18,470 --> 00:05:21,120 and manipulate strings. 76 00:05:21,200 --> 00:05:28,030 So in order to create strings the most direct way to create a stream is to actually use the string literals. 77 00:05:28,050 --> 00:05:33,680 OK so for example let me actually comment out these lines of code here and I need to refer to the name 78 00:05:33,680 --> 00:05:37,930 of the string class the name of my object is Esti are one. 79 00:05:38,240 --> 00:05:40,820 And that I put in an assignment operator here. 80 00:05:40,970 --> 00:05:43,920 And then I can actually put into double quotes and here I can. 81 00:05:43,950 --> 00:05:48,160 Just putting a value here. 82 00:05:48,170 --> 00:05:48,580 OK. 83 00:05:48,610 --> 00:05:52,940 Inside the double quotes and then I need to put in a semicolon at the end of my statement. 84 00:05:52,960 --> 00:05:53,520 OK. 85 00:05:53,660 --> 00:05:58,500 So here as you can see this is the most direct way to create a strange. 86 00:05:58,560 --> 00:05:59,670 OK. 87 00:05:59,820 --> 00:06:09,760 Whenever the compiler encounters a string literal in your code it creates a string object with its value. 88 00:06:10,170 --> 00:06:14,010 In this case OK with its value in this case of value. 89 00:06:14,100 --> 00:06:14,530 OK. 90 00:06:14,550 --> 00:06:21,870 As with any other object you can create String objects by using the new keyboard and a constructor which 91 00:06:21,870 --> 00:06:26,490 I actually showed you two examples earlier in this tutorial. 92 00:06:26,490 --> 00:06:34,050 The string class has 11 constructors that allow you to provide the initial value of this string using 93 00:06:34,260 --> 00:06:35,260 different sources. 94 00:06:35,270 --> 00:06:42,370 Distraint class is immutable so that once it is created a string object cannot be changed. 95 00:06:42,420 --> 00:06:47,550 If there is a necessity to make a lot of modifications to strings of characters who can actually use 96 00:06:47,730 --> 00:06:50,900 the string buffer class or the string to be the class OK. 97 00:06:50,970 --> 00:06:58,330 And now I want to actually show you some of the effects of a strange class in order to manipulate these 98 00:06:58,510 --> 00:06:59,430 string objects. 99 00:06:59,460 --> 00:07:00,150 OK. 100 00:07:00,570 --> 00:07:06,290 Methods used to obtain information about an object are known as accessor methods. 101 00:07:06,320 --> 00:07:12,250 OK one access and method that you can use with strings is the length method. 102 00:07:12,360 --> 00:07:20,220 So let me repeat again methods used to obtain information about an object are known as accessor methods. 103 00:07:20,400 --> 00:07:27,750 One access in my faith that you can use with strings is the method which returns the number of characters 104 00:07:28,320 --> 00:07:31,150 contained in these in the string object. 105 00:07:31,170 --> 00:07:34,470 And now I want to actually show you those examples here. 106 00:07:34,610 --> 00:07:43,110 OK so now as you can see here in line 26 I created a string object and the name of my object is a string. 107 00:07:43,140 --> 00:07:44,500 One Esti are one. 108 00:07:44,520 --> 00:07:52,950 OK so now I want to actually create an integer value but in order to actually hold the length of this 109 00:07:53,160 --> 00:07:54,160 string object. 110 00:07:54,230 --> 00:07:55,960 OK so now. 111 00:07:56,010 --> 00:08:04,600 So the data type of my variable is int and the name of my variable is as thrain Len. 112 00:08:05,060 --> 00:08:05,790 OK. 113 00:08:05,820 --> 00:08:08,660 And then I need to put in an assignment operator here. 114 00:08:08,970 --> 00:08:14,550 And then I refer to the name of my object t r want that Len. 115 00:08:14,850 --> 00:08:18,910 As you can see here this little method is an accessible method. 116 00:08:18,950 --> 00:08:26,430 OK so an Access and method means that this method is actually going to obtain information about this 117 00:08:26,520 --> 00:08:27,080 object. 118 00:08:27,090 --> 00:08:27,690 OK. 119 00:08:28,050 --> 00:08:29,850 So the name of this method is Len. 120 00:08:30,120 --> 00:08:37,190 And the return type of this method is int and this method is inside the stream class. 121 00:08:37,200 --> 00:08:42,610 OK so if I choose this method now and I need to put in a semicolon at the end of my method. 122 00:08:42,690 --> 00:08:45,300 So this is Thring less valuable. 123 00:08:45,300 --> 00:08:49,620 Now holds the length of ds s t r one object. 124 00:08:49,620 --> 00:08:50,210 OK. 125 00:08:50,400 --> 00:08:53,610 And now if you want to output this value to the console. 126 00:08:53,640 --> 00:09:00,930 I just need to type in here a system that's out that princeling and an inside the apprentice's I just 127 00:09:00,930 --> 00:09:04,930 need to refer to the name of my valuable as string string length. 128 00:09:05,100 --> 00:09:08,010 OK so now I need to choose this option here. 129 00:09:08,010 --> 00:09:09,050 String length. 130 00:09:09,240 --> 00:09:12,380 And then I need to put in a semi-colon at the end of my statement. 131 00:09:12,480 --> 00:09:18,460 So now if I add on my project as you can see this value is output to the consulate number 7. 132 00:09:18,480 --> 00:09:29,800 So if you actually count the length of this string here as you can see one two three four five six seven. 133 00:09:29,950 --> 00:09:34,580 OK so this value is the value of the string length variable. 134 00:09:34,600 --> 00:09:39,820 Ok so this is the length of our string object. 135 00:09:39,850 --> 00:09:40,610 OK. 136 00:09:40,870 --> 00:09:45,800 And another method that we can use on String objects is. 137 00:09:46,060 --> 00:09:49,240 For example let me actually comment out of this line of code here.