0:00 categorize the Java programming language into five parts firstly we will understand how to write the first Java program then we will completely understand about the compilation part we'll do some deep dive we'll do some research about the compilation part and again uh we will do some rearch research about this execution part after that I will help you in installing the Java software so after understanding these three things installing uh Java software will become very easy right uh after that you after installing the Java software you will understand the control flow of first Java program in the operating system with respect to the operating system how the Java
0:45 programming language will communicate what are the things that the programmer has to do to ensure that the Java programming language is getting communicated with the operating system course the operating system and the program programming language has to get communicated to perform the compilation and the execution because we will be writing the program in the the form of text file and this text file has to go through a lot of process before getting executed right this process will happen on the operating system that's that understanding is very much required right so you will understand this one by one uh I am sure that you will get much Clarity on this after
1:30 completing all these five categories we'll get much Clarity on the Java programming language so far we have discussed everything theoretically let us understand little bit programmatically uh so let's get started so firstly I will write the simple Java program and we will uh like you know post we will do the postmortem of each and every part each and every key Okay so we already know uh like we have already seen many Java programs and I always used to write my code like this we have a
2:16 class so let me take the name of the classes first any meaningful name it can be right there is some reason behind this colors will explain you public static name print this is a typical Java program isn't
3:02 it hello Java you find this in your textbooks and uh so this is the uh like you know so many things happen behind behind this Java code when you start compiling and when you start executing it may look like a f Lin of code but so many things will happen internally but if you understand those Concepts then writing you know uh like defining a code or declaring a Java code is going to become very easy there may be only five five lines of code but internally many things happen in fraction of seconds we'll understand uh how these
3:47 things work internally and what what are these keywords actually we'll understand everything to let me increase the B size this is a typical Java code and if You observe I have used a set of me keywords just tell me one thing uh like you know this is a Java code but if you look at it anyone can read this it is completely readable readability is very so it is like everything is in English who reads English I mean uh who
4:33 knows English they can understand this very easily understanding in the sense it is very close to the understanding of course uh like uh the words are very much readable but interpretation is little difficult we are going to understand the interpretation interpretation means how this code is going to get communicated with the computer that is what we call it as what interpretation let me write that let me uh write the notes Here Java program if you see this not only Java
5:19 program if you want to like you for example in your college you are asked to write an essay an English essay right you are asked by your English lecturer to write an English exay on politics right so what you will do before even starting uh before even writing an essay you will follow some set of rules and regulations is it when you are asked to write an English essay what you will do you will follow some set of rules and regulations right and the rules are like uh you will ensure that there is the essay is divided into three
6:04 parts one is Introduction part right and second one is uh body paragraph right and third one is conclusion you will take all this three parts into the account and uh you will start drafting an essay right and also you will ensure that the sentences are properly organized firstly and we will also make sure that uh the paragraphs are divided properly or we can the paragraphs are arranged in the orderly fashion right so introduction and uh sentence formation organiz organizing the sentence in the right format and also ensuring that the
6:51 paragraphs are properly arranged right these are some rules and regulations that you have to follow and apart from that we will also ensure that the spelling spings are correct you will do spell check very important right so based upon this this essay will be interpretated interpretated in the sense the vocabul that you use the words that you use and the sentence that you make you know it should it should be communicated in such a way that the thoughts that you are sharing should be communicated the same shot should be communicated to your teacher there should not be any
7:36 miscommunication this communication should not be there your understanding should you should make sure that your understanding is completely reachable to your teacher but sometimes what happens uh you may be writing uh your essay in your own understanding but it will be misinterpreted misrepresented or miscommunicated right that that things you need to take care to ensure that the essay is properly communicated to a teacher right that is what we call it as what interpretation interpretation interpretation understanding understanding the things in the correct way right likewise when you want to write a Java code you need to follow some rules and
8:24 regulations right what are the rules and what are the regulations and uh these things we will discuss uh we are going to discuss now right if you see this code see look at this first line so I have uh I have used a class and I have used something like first Java like public static wide Main and things like that system out print right so this is just a code and this will this code will ensure I mean uh we are designing this code just like an instruction this code will uh communicate with the computer right these are the instructions that will communicate with the computer to give the relevant
9:12 output right of course this is high level language that that can be understand by the humans anyone any person who knows English can read this can read this it is very easy to read right you see this you can read but you cannot understand you're not able to do the interpretation you're not able to understand because we are just started learning the Java right so what happens is let me write some Theory but I can say Java is a high
9:58 level programming language which is easily understandable by the humans or I can say it is easily readable by the humans by the humans and it is close to the understanding see if if you take Ganesh as an example Ganesh can read this code without even learning the Java can just read it like like a like a class first
10:45 Java public static viid very readable right but understanding it is not as easy as reading this things isn't it so that's what it says it's high level programming language which is easily readable by the humans is close to the understanding if you do some research you can understand this code right so it is used to communicate with the computer computer and a programmer can pass instructions
11:30 instructions are in the in the form of data a programmer can pass instructions in the form of data with the help of java and this instructions are interpreted by the computer to give the relevant output which is called as information this will make more sense in some time right what I what I'm trying to say Java is high level programming language which is easily readable by the humans you see this you can read this code isn't it and uh it I mean though it
12:18 is readable it will be little difficult to interpret means understanding this will be very I mean little difficult because this is a program which is readable but uh you to understand this you need to understand uh how Java works right that's why I said it is close to the understanding and it is used to communicate with the computer so this simple code will communicate with the computer to give the relevant output so what we actually do we'll pass some data right this data will be manipulated and uh this data gets executed and the output is going to be what the information right we send data and we get information right so when someone is asking what is
13:03 Java program this is a simple explanation that you can give in your own words you not have to like remember some difficult definitions things like that they don't expect this this simple definition can be this this makes more sense right and if you see in the first Java program so I have uh there are many words this is a word class is a word right and first Java this is another word and we have public this is another word so there are so many words right these words are called these words are programmatically called as keywords right this word this class is a
13:49 keyword and this public is a keyword things that are in black things that are in black in color they are called as what they are called as so keywords let me specify that so class so class I can say that class is a keyword you will understand what is what is a keyword is a key and first Java first Java is not a keyword first Java is an identifier okay I'm just introducing you some technologies first Java this is called as what
14:42 identifier and uh this Public public in Java uh we usually call it as access modifiers access modifers right and here we have what system system is a class predefined class and here we have out out is nothing but uh reference variable reference varable print tent print tent is called as method
15:27 predefined method and we have uh something here hello Java H Java is nothing but the data text Data I can say this as what text Data data right so here if you see uh public I have said access modif static is that right static we call it as non access modif we call it as what non access modifiers non access modif and here you can see a word like a keyword like void
16:14 vo is called as return type return right and uh this main is called as what method name I will give you explanation brief explanation about each and every keyword name right let me
16:59 is a keyword and this is identifier public is access modif and the system is predefined class is reference variable this is predefined method is Text data and uh this is non access modifier this is WR type this is Method name right we have this right this is class name three def class class and this is uh user defined
17:47 variable this is called as identifier we can say that can simply say that identifier for the time being I will explain [Music] see uh we did some postmortem in the Java first code right so this code has been categorized into like many uh many parts so there is a called we call it class as a keyword and this public is called as access modifiers right so if you ask me sir why did you write first
18:33 Java AR GS and allow World in red this question must hit you right previously I have written this first Java and this ORS right and this Sol world I have taken this words in the red color it means these things are the programmer design programmer can choose any kind of ver here any kind kind of uh words to be written here it can be first first Java as per you it should be meaningful that's it you can write anything here can be first. Java first Java it can be second Java whatever it is the name of the class should be meaningful and this args right args nothing but it was uh like you know what
19:21 we call it as a meaningful uh a meaningful word args means a short form of AR you can write anything here so this is allow Java is a text data right if I pass allow Java here output is going to be allow Java if I if if I pass any other any other sequence of characters the output is going to be that sequence of characters that's that's why I've taken all these things in red in red color right now the question is what is a class we have already discussed about what is a class and what is all this access modif what is this pred defend class and what is this reference variables these questions are these questions are hting us like anything isn't it we will understand that right in Java let me write it
20:10 here Java key they are actually they are the res ver in Java that is used to deare a variable method or class in
20:57 addition it will also help to communicate with the system to get the desired output right so there are totally 51 Reser words in Java 51 keywords in Java if you learn this all 51 keywords Sava will be completed okay what are those 51 keywords right let me show you
21:57 that let me minimize this I said there are 51 ke in ke in Java if you count this the count won't be up to 51 50 keyword are I'll tell you I will make it 51 so these are the keywords if you understand each and every keyword the Java will be completed right and if you see here these things are constant and go to right is not anymore I mean uh is not
22:44 in the Java programming language anymore right the remaining things are here right so abstract asset Boolean break bite case character and many are there and if you complete all this the Java programming language will be completed right you see I have mentioned that class is a keyword right class is a keyword and if you see the class class is here so it is a keyw and if you see Public public I mentioned this as access modif but if you see Public public is also mentioned in the keyword why it is like this
23:29 that question I will answer now and again if you see if you go to non access modif non access modifer I have uh stated static is non right but if you see static static is also why it is like that and why the count is 50 here and I have mentioned that there are 51 keywords in right so remove this two constant is not there and go to is not there right apart from this two so we have
24:26 another n is not included so we have uh to remove this two there will 4 and there is one more thing called true or false please include this three as well and this constant and this go to is not part of the Java programming language anymore and we have all the keywords apart from this and this null true and false even though I mean usually they they do not
25:13 call this as keywords instead they call this as identifiers which cannot be used identifiers that can't be used by the programmers programmers to Define a variable name or user Define name right so class if you anyone ask what is class so let me write that here
26:03 what is a class in the class is one of the keywords of the keyword so of java that is us to the blueprint of the requirement you have already seen this what is class in our previous video I have given a brief explanation about the class thing class is nothing but it is a blueprint of our requirement right and we can also say that class is one of the keywords because if you see here class is listed under under the
26:52 keywords that is it see class is here classes is under the key keyword is one of the keyword and which is used to create the blueprint of a requirement you may you may be having any requirement for example let say that you want to build a functionality addition functionality you cannot build that functionality directly you have to ensure that the functionality is getting built inside a class I can say also say that the class is also called as a container container which could have properties
27:38 and behaviors so behaviors in Java it is called as methods properties in Java we call it as variables there it is very simple explanation straightforward explanation class class is a keyword and that is used to create the blueprint of any requirement right and uh since class is a keyword you cannot specify the class without any name for example if you are talking about any kind of data you need to ensure that the the data is getting an identifier right for example uh I want to design a blueprint I want to design a
28:25 blueprint for my for my house I want to construct an house I want to design a blueprint right what I what I want to construct I want to construct an house in order to design a blueprint for my I need to use the keybord called keyboard called class right and the class should have the opening parenthesis and a closing this is called as boundary right and we uh completely call this uh part as a container that's that's why I mentioned class is also called as a container right in this container we are going to have what variables variables in the sense
29:10 data secondly we are also going to have what behaviors behaviors are nothing but what functionalities we can say it as methods right so this should be fixed you cannot uh like you know the syntax of class is fixed it should be in Lower Class always if you see here all the identifiers are in lower case letters this observation is required all the identifiers that that we coming across should be in lower case letter right and if you see this we have seen this in the naming convention you want to name a class if if you want to give any name to a class right the class name should always starts with capital
29:57 letter you have seen this in the naming conventions if you don't remember you can check that video the list right so what is a Class A Class is a class is one of the keywords of java that is used to create the blueprint of blueprint of any requirement the class is also called as container why it is called as container because all the variables and behaviors are contained into a single entity entity is producted it is secure right so if you see this if you see our first Java program this first Java there is a class the name of the
30:42 class is what here in this case it is first Java so this classes a behavior behavior in the sense in this case we have a method right so of course the having variables and behaviors are optional the secondary but if you want to have variables and methods in a class you should have that in a class want to have you want to keep all these variables and behaviors or all these data and methods inside a class you cannot have this outside the class should be encapsulated inside the class right just like a capsule just like a medicine capsule right when the medicine capsule all the like you know medicines and
31:31 protein medicine or any chemical medicines will be contain will be encapsulated in a capsule right like that you want to perform any operation or any design any functionalities design that in a class that is a compulsion that is not what that is not the suggestion that is a compulsion what is a compulsion you have to design everything in a class right class is going to act as a container if you want to perform design any functionality or operation make sure that it is designed within the class hope this is making some sense this is class class is one of the Java
32:17 right secondly we have what uh we have an identifier we will uh I will explain about this identifier before that we'll see what is public on top of the public on the left side of the public I have mentioned that it is an access modifier if it is an access modifier why it is declared here public is listed in the keywords and why we are calling it as access modifers I will give you the explanation now right what is public
33:03 in what is a public access modifier modifier or simply I can say what is a public word in so the answer can be public is one of the access defs that is used to give the visibility to the class methods of variables don't
33:52 worry about this we will understand this public is one of the access modif that is used to give visibility to the class methods and variables the access modifiers are categorized into four types since we are discussing about public it can be public it can be private it can be default lastly it can be
34:39 producted producted so this default is different and uh this default is different this is in capital D okay this is in don't get confused this both are different this is different this is different what this default means if you're not specifying anything like public static producted so in this case you can have your Public Access modifier the list of access modifier I have already categorized the access modifier into four types public private default and protected right so since it is here we have written it as public but you can also have private you can also have protected right you're not having anything is going to be like
35:24 default it's going to consider it as default it means you won't specify this word you don't write anything it is going to be default there is no modifier there is no modif it is going to act like default these are the four access modifiers in Java right and here the takeaway the takeaway is all the access modifiers or fers can be Java key Java
36:13 key but not all the Java keywords are access let me give something all the access modif are Java keywords except default capital D default means no access modif but not all the Java keywords are access modifers hope this is making some sense right so access modifiers are called as Java keyword
36:58 it is subcategory access modifier is subcategory under Java that's why it is reflecting if you see public you can see here public is here
37:53 okay I T what it is no worries I will write it once again so what I was trying to say is all the uh access modifiers are keyword but not all the keywords are access modifiers right access modifiers are categorized into four types public private default and producted and default is nothing but if you do not use anything that is going to be treated as default so let me take you some here so access modifiers and non access modifiers we'll discuss about this non access modifiers and this is these are
38:40 the access modifiers usually you do not write default if you do not write anything it is going to be T default that's why it is called as no mod right this is making sense so and thirdly we will discuss about what uh non access modifier let me write instead of that I can write what is static in what is first
39:28 I can say that the static is one of the non access modifers in Java it is us should to deal with the memory allocations for the timing just understand that static keywords are going to deal with the memory orientations uh there are many on access in Java and again all
40:14 the all access modifiers are Java but all the Java are not non access moders right so public static public is an access modifier and static is a non access modifier and if you see stat non access modifier these are the these are
41:00 some of the non access modifier static final abstract synchronized transient volatile and stri each and every keyword has has some operation it will perform some operations right after this we have something called void void in Java void is called as a one of the written types one what is a white keyb in jav what is
41:54 avoiding why is one of the WR tyes return types SC primitive type or data type instead of wi you can place primitive data types or else nonprimitive data types you do not want to place primitive data types or non-primitive data types in the place of void I mean uh in the in the place given here it is necessary to keep this fill this place as word so what do you mean by that sir right so we already know
42:40 what are the Primitive types and non-primitive tpes we have already discussed these things so let me uh introduce a sample picture so this is a sample T table of data types in place of f you can write P you can write short in Long float double Bo these are the Primitive type and these are the non-primitive type so this place is not only restricted to vo depends upon the programming output this place this vo place can be replaced with the Primitive types or non- primitive types
43:26 so we will understand these things in the methods Concepts when we are developing methods these things will make more clear for the for the time being just understand that this void is nothing but it's a it's called as return type I need you to uh like I'm just feeding you with this new terminologies return types means this is a return type if anyone is showing a program you must be able to uh like understand each and every keyboard if I if they point you to public you should should be capable enough to say it as access modifier if the point you are static you should be capable enough to say that is a non access modif I need to I'm just feing it with this teries still we have a long way to go we have a long way to go this a
44:13 simple Java code uh this is how the Java code can be interpreted right so this is what uh what is a void in first program language void is one of the return types the return types can be primitive type or a nonprimitive type so instead of qu in the place of it you can also replace it with B short long so again the main we have a main so main is nothing but it's called as a method name so this is a predefined method name right understand one thing here right so we have written the first Java program so in whatever the program that you write the main method is
44:59 mandatory the Syntax for main method should always be same you cannot change the syntax syntax of the main method should be same it should be like public static void and it should uh like internally have string string array this can be different a GS can be anything but this prototype should be same public static this this whole whole instructions the entry point and the exit Point me we this whole instructions within this entry point and exit point we'll call we call it as the main method you cannot change this main method this how the Java will defend you should follow this because it will act as an entry point whatever the
45:46 instruction that you giving in this main method will get executed this should be same we're just trying to understand some terminologies on top of the main method the access modif what are the non access modifers so there is a static what is the static static is nothing but non access modif what is non access modifier what are what what are it uses we'll discuss that I already mentioned that uh we will complete each and everything right because by completing understanding each and every keyword the Java programming language is going to get competed first of all let us interpret internally T many meanings we are trying to understand those words and those Technologies right if if you see here I have system system is nothing but it's a predefined class it's a predefined class and out is
46:34 nothing but this reference variable is called as a reference variable I can also say that predefined reference variable predefined reference variable and this are predefined method this class this variable and this method these are the internal things right this is just like a what we call it as uh combination of keywords if you use this and whatever the data that you're writing here whatever the text data that you giving here it will be displayed in the console as simple as
47:20 that right all this the combination of system out print right and what whatever the text data that you giving inside inside this brackets in the double qus that will be displayed in the console we call this as what Text data right so let me understand that let us understand what is
48:13 main what is the meain so what we can say is the name of the method is the predefined one predefined one is nothing but uh these things are defined by the Java people who have designed this Java program they have defined this that's why it is called as PR it is an identifier identifier or I can say that it is a predefined identifier we def find identifier that can't be changed and can't be used
49:02 anywhere in the Java program anywhere in Thea a programmer cannot use this use the word main anywhere in the Java program apart from the uh apart apart from the uh method apart from the main method you cannot use this word any that's why it is called as what uh that's why is called as predefined there it cannot it has some restrictions programmers cannot use this name anym right these are some this is one of the internal rules right and the syntax of the
49:50 M could always you cannot change this syntax the syntax of the main should be like public sted M string array so this is the entry point this is exit point and uh all the sections inside the inside this method will get executed only the
50:36 instructions that are defining inside the main method will get executed right so this is a entry point this is this is how the main method should be defined we cannot change this you cannot keep uh instead of small using the lower case you cannot use upper case this will be that will be tactical should be why it cannot be used that is a rule that is a rule rules they are the rules and regulations the starting I have already explained why the essay should be written in such a way that the essay is categorized into three parts introduction part body part and the conclusion part even though like you you can you can write to in your own way can scribble you can do a lot of things that no one can understand but it has to get interpreted it has to get understand has
51:24 to be by your teacher likewise this is how the ja the operating system is going to understand our language are the rules should be small I mean the it should be lower case should be what lower case and everything should be lower case public static vo name instead of a GS you can write any meaningful name can write uh any name any meaningful name this is optional you can I mean you have to write something but you can it can be anything it can like it's not like OB actually I have faced one interview question on this main meod the interview
52:10 question was like they have given me this for snipp right and uh they have asked me if uh this code will work static public they did a little they they just interchanged this public and static instead of public static this is the sequential order you will find this in your textbooks this is how the syntax is developed public followed by Static void main right and uh this was my question static public void this is correct this is this was the question that I have faed right so this is also
52:59 correct both are correct you can interchange this access modif this is access modifier this is non access modifier both cannot can be interchanged the place is not a big de they place place value I mean their place holders are not the big deal they can be interchanged public static V me is same as static public W no issues but uh this you cannot do this this cannot be this cannot be happening static Public Access modifier and non access modifiers you see here access modifier and this is non
53:44 access modifier they can be interchanged there will be it is not going to make any any issues this is the one of the interview questions that inter question question like can interchange the places of and in the main main the answer is what the answer is yes yes there will be
54:42 no output will not get affected right is the entry point all the instructions that is find the
55:29 name will get executed seen sh right so this is what the meaning for main method and let us understand what is this string we have to understand each and everything and we have understand what is system what is what is after understanding each and everything right we will understand how all these keywords cooperate together to perform the compilation how all this each and every keyboard is operating together to perform the compilation inside the
56:16 compilation there are there will be so many uh operations involved to generate the bite code right these are the human human instructions these are the instructions that can be understand understandable by the humans right this instructions needs to be converted into a different language now we are talking about high level language this instructions has to get converted to a low low level language which is nothing but machine understandable language how this conversion is happening internally we will we will discuss that we will discuss that tomorrow okay uh most of the part is Theory agree that but uh you know this things are necessary this topic is necessary these
57:03 terminologies are mandatory to understand the future topics any doubts so far you have any doubts you can you can stay in the call if you do not have doubts you can can loog I mean you can you can discon what about you sh if you have any doubts you can stay in the call and can ask me what about you ganes okay all three have no doubts then can I ask you some questions
