Java Fundamentals Unveiled | Java Training | Edureka Live

Key Takeaways

good afternoon and good morning everyone welcome to the session on Java certification program my name is Rakesh Kumar Singh I'm your host and your trainer for this Java certification and selenium certification plus manual testing and uh other devops related courses so our agenda is to understand the Java fundamentals what are objects what are classes methods access modifiers flow of the controls and arrays this is pretty much huge topic but I'll try to touch base on lot of the pointers and I'll try to make you super comfortable with one of the programming language before moving ahead let me tell you my own story I am since you know that I'm coming from a background where in the programming language was not that important okay I I come from very professional background that that is a petroleum engineering very less Engineers you will find around and after that when I moved into the IT industry I started my career from automation only so you just think uh whatever the hype is there in the market related to the programming language whether it is very very difficult or whether it is uh you will be able to learn it or not okay the fear of facing the fear of going through this component okay and plus people will also have foro that is fear of missing out if they do not learn so um to start also there is a fear and if they do not learn this thing that is also the fear in their uh mind same thing I also had uh but I got very wonderful teacher over here uh like eight years back and because of which uh in I was able to understand every concept of java till date I do not I like whatever things I learned in the classes uh nothing were missed okay so if you have a great teacher great explainer and uh who can help you out in all the learning that plays a vital role because you develop your understanding plus you develop your interest also into the subject it is because of the teacher that's what you find out over here in edureka let's get started with introduction to Java what is Java guys um Java is a name given little later on to this programming language with before that the name of this programming language was Oak o a k we have a plant right tree Oak I'll just write it o a k initially this project was Oak it was actually created keeping this in mind that we do not we want to create one type of a programming language which is independent of the platform what is the platform Windows Linux Mac OS or whatever other uh operating systems are there at that point of time so it was created in 19 1995 and this was given name as Java because uh this project wherever this was going when Indian was also there uh in this uh team in the company of sun micros soft uh company and they used to drink one coffee and the Coffee Bean name was Java that's why this project was named as named as Java later on okay what all features it try what all features it provides us so let's go ahead it's a high level programming language okay learning c c sh or C++ becomes little bit difficult because it is lowlevel language lowlevel means when you have to do the coding at the chip level okay vsi very very large circuit integration uh testing if people do they write they use their preferential languages C okay now the father of java is James Gosling okay he was the one who started started this uh project and uh this sun micro system started working in 1995 and it was released in 1996 I think around the python was also released in lumsum this time only 95 or 96 okay so both are brothers and they have celebrated their silver jubile in recent time itself okay now it is free and open source uh software you know uh most of the softwares like whatever the softwares what whatever these languages are there they have to be free if they are trying to provide the lot of functionalities now lot of time people will also uh think python would be really very good why we are learning Java let me talk to you about each and everything okay all those uh things I will uh come across and talking about Java yes it was previously known as Oak now this concept the tagline of java was Vora w r a means write once Run Anywhere means if you are writing your code in in uh Windows operating system and you take that code in your pen drive put it in uh Linux operating system and if you have Java installed in there okay you can execute the same program which you have written in Windows so this is known as platform independent platform over here is the operating system means it does not bother whether you have J whether you have uh Windows Linux Mac OS um whatever operating systems you have okay so these all supports it provides okay now what all are the features of java it's easy to understand a lot of people will tell you will try to misguide you if people have very less knowledge they talk about the functionality a little more if people have more knowledge they'll talk about the functionality very less because it takes little bit of calories to digest the facts and and keep it with ourself correct a some or the other two three calories will be burning in the mind if you have learned something okay so this because that's why people will be indulged in keeping all the knowledge little safe so they will not talk um much about it now people who have less knowledge what would they will tell they will always talk about the language in this way like um what Java is a very huge language even if it is 3 4 years of time you cannot learn full Java yes it is true but uh you cannot do the same thing with python also right lot of libraries are there unless and until it is needed for you why you will learn it okay for the development purpose if you have to learn Java only few topics are there which you need to learn okay for testing purpose if you have to learn Java it will be even 50% of what the development people are learning okay because development people or developers will be actually working on Java uh in a full stack manner but when it comes to the test Engineers they will be come they will be utilizing this Java only to communicate with one of the tool selenium or any other tool getting so uh it is very easy to understand and it is very robust uh language okay it is little bit vast but we need not to understand that it is vast okay we need not to understand we need not to learn everything okay we have to only learn eight to 10 topics that's it and everything would be fine okay for 10 to 12 years of time yes I'm saying it correct because uh until unless those libraries are needed as per the project the new libraries are needed as per the project you should not go ahead and learn that okay every every language or every topic that you will learn in Java can be Max to Max of 20 minutes of time or very less time 2 to 5 minutes okay these small small topics are there in Java very small small topics data types variables literals means values AA methods now changes into the methods Constructors this and that those all things will come so Java is the collection of small small topics that's why people say who have not succeeded that's why they say that it is very vast okay it's not vast if you even though if you want to drink the ocean you can drink without any issue and even a single comma you will be able to remember okay now talking about this Java is easy to understand yes absolutely it's very very easy to understand compared to the python people will say that python in Python we need not to write extra lines of code in Java we are writing two lines extra code a that might be taking more memory right no it's not after after the uh after the Lambda function came in okay in 1 Point eight version um in Java also we started utilizing writing our code in such a way that it whatever the code we are writing we can write it in very less number of lines okay so these all functionalities these all things are actually there so Java is very robust okay robust means it is very strong okay and it is strongly typed language so capital letters are actually treated as capital letters means uppercase is upper case and lower case is lower case both if you are writing uh like this numbers any variable name or if you are writing numbers here it will not go through the meaning okay it will go that this number and this number is totally different because it is uppercase this is lower case Okay so Java is actually strongly typed language also it is portable you have seen you take the code from Windows and you can get it work on the any of the programming language AA okay it is distributed objectoriented programming yes Java is actually not 100% objectoriented programming language it is 98% objectoriented programming language 2% it is procedural language like the python and all okay python is also procedural language itself so uh it is platform independent we have seen it is safe and secure okay and it is multi-threaded okay so these all are the features of java that we have seen cool now let's talk about next objects and classes before that I would like to take you to my drawing board and over here I would like to explain it to you how do we write a code in Java okay code code code program program program this is what you have always learn and this is what creates lot of tension in our head whether you will be able to learn this these things or not correct now it's my responsibility to give you a very nice Journey right now let's talk about what is programming in Java okay whatever the programs you write in Java whatever the code you write in Java with that piece of code you are trying to give certain instruction to the system and your system will behave as per the instruction that you have given correct now to give this instruction to the system okay then we have certain syntax okay syntax means a way of writing the code all right now how do we go ahead and how do we write this we are going to write it like this any program in Java we write it like this first keyword that we write small letter c l a s s that's it after that whatever name you want to give that you can give uh say for example class test okay so first letter of the class uh will be capital okay so here class keyword after that class name will come okay after that you might have seen this curly bracket open and over here some little below the curly bracket is closing you know what it is this curly bracket open and curly bracket close what it is it denotes the body of the class body of the class okay body of the class any piece of code that you write any piece of code that you write that will come inside these two brackets only okay lot of people will be confused which bracket is closing where that only the main situation they get worried about it okay no need to be worried okay if you're using certain type of editors which I'm going to Showcase it to you okay by really executing this program and showcasing like how programs ex actually execute okay all of your fear will be gone okay this is how we write the program inside any program two things will be there okay um say for example I have really I have a dog he is sitting at my leg and his name is Oreo okay his name is actually Oreo so if I just try to remove the name of the class from test and I try to keep it as class name as Oreo okay this is the name of the class now inside this whatever the behavior I have to design for this um dog okay that I can do okay but if I have to say what is the name of um this dog age of this dog color of this dog these all are this one short one one word information so one word information when you have to keep in a class you put it inside very variables okay so one variable I'm putting it as name name equals to in double quotes I'm writing Oreo why I'm writing double codes you'll learn it later because it is collection of characters o is one character R is one character e is one character o is another character collection of characters means string so this type of data this is data this is variable name so what type of data it is it is of string type so I'm writing over here string okay this is how we keep this is what this is what variable correct you able to understand now AA what is the behavior of my class okay now let me let me delete this okay now what is the behavior of my class uh class is my Oreo and that is a dog what is the behavior of a dog now behaviors are actually defined by methods in a class A how do we write methods do not be worried about how I'm writing methods okay one one behavior I'm creating public static void do not ask this is known as access specifier this is modifier this is uh return type okay we dwell uh we dive deeper into these all Concepts after this I'm writing the behavior of my class is bark okay bark okay even though he bars really very less over here like this this curly bracket open curly bracket close will come now what is this this is body of a method body of a method now do you think we will only have one method no boss you are not restricted by anything you can have a number of methods seriously now public static void this is a syntax of writing any method so public static void eat his favorite thing is to eat all the time even though he doesn't know like when the stomach is going to be filled so um this is again body of the method now you tell me if I talk about these two things these two things are nothing but the methods correct these two things are nothing but the methods a method is actually describing about the behavior correct Behavior or I should say it as action now I have only written one variable this is what variable correct this is what variable and using variable variables okay I have only one variable age color complexion everything I can write so using variable using variable class knows something class knows something and using methods using me methods class does something okay so this is how we write our programs and nothing extra things will be there inside the classes if you are having for Loop if else this and that everything will come inside the methods okay so uh variables are of two two three types okay look uh first they are divided into two parts okay where where they are actually described inside the method local variable outside the method okay Global variable okay now in global variable also they have two parts okay they are static variable and non-static variable okay and we also have reference type of variable so we try to dive deeper into the all of these Concepts let me show you little bit of examples related to this so this I'm just trying to open up one of the IDE or integrated development environment okay this we need to install and over here you can do programming and this is one type of a software where you uh this is actually not needed at all okay so but to make your life easy when you have to handle number of files and you want to have little bit of uh efficiency you want to use certain plugins okay you want to see your code in a little beautified way okay then you need to use um editors okay so this editor opens up like this I'm using a little older one one year older one and this is how it opens up Let it open now in this uh this is known as Eclipse okay it's not needed that you are writing your code over here Al only you can write your code in notepad++ also okay now over here also you can write your code this is Notepad Plus+ or you have a notepad you write over here you can write it like this class uh test or class Oreo okay Oreo okay this is how you can uh put your brackets so this bracket if you keep your cursor over here this bracket will get highlighted the closing bracket will get highlighted AA okay now let's have a look whether it is open or not yeah it has been opened it would be very better if I tried to show you the project over here itself how do we create the project this is also very nice if you go to the uh file if you go to new one Java project is there go to file go to new Java project is there let's create a Java project and which version of java you are using you need to install Java before okay then only your Eclipse will work otherwise Eclipse will not work okay so let me create one project as demo and I want to use 17th version I can use 18th version also but let me use 17th version click on finish left hand side you can see that the project would would be created demo project has been created I do not want to create any module don't create AA you see very simple project has been created all the Java 17 libraries are over here so that whatever the program you will write um every program would be understood by the system otherwise if you do not have JRE jars okay how will you how will your program be understood okay public what is public what is static what is void all of these things no one will understand so over here if you have to write any program just create let's create one folder SRC means SRC is over here SRC means source code source code means your code okay now in this SRC let's write uh one folder I'm creating that is known as package you keep your code in folder itself but that folder name would be package it will be considered as package okay so this is code inside this let's create a class so right click onto this right click go to new and let's create a class class means one program of java what name you would like to give Oreo o Capital re EO Oreo now let's have a look okay your program is created over here left hand side is known as project Explorer you can keep all of your uh all of your projects over here 10 20 50 60 projects whatever you want to keep the projects you can keep over here doesn't matter now inside this if you want to create like uh the name of the dog what is the name of the dog you want to store it in something string name is equal to Oreo integer type of data I'm going to store int age type of a variable inside this I'm saying my Oreo is around 1 year old okay now let's create certain behaviors of it public static void Behavior first behavior is bark okay very less even though we were searching for him for 1 hour he was just sitting be beside in one room he did not bark so and over here inside this behavior I'm creating inside this whatever type of coding whatever type of logic you want to keep you can keep as of now I'm just trying to print something okay so that I get to know that my control was over here okay so I'll just write system.out.print lent this is one printing statement okay we Ed we usually Deep dive into this also system is a class that's why s is capital out is a variable and print Ln is a method system. out. print Ln it does not change inside this whatever things you will write it will print okay now let's create another method also I am not very much satisfied so public static void eat he likes to eat so block of um method also I have created system.out.print tent and over here I would like to write Oreo eights okay now would you like to uh create another me method also he plays a lot all the time he likes to play but public static void play yes why not he likes to play okay system uh system.out.print Ln uh overo pleas these many things you have written three behaviors you have created with which class does something and two variables name and age you have created with the help of which class knows something class knows that what is the age of the dog class knows that what is the age of what is the name of the dog whenever you have to execute right one Papa method will be there Papa method means it is informal word that I'm using Papa method means uh which is very important method without which the execution of the class is not possible okay so to execute any class we need this method so public static void main you cannot change how does it look like okay inside this uh string this square bracket open Square bracket Clos is known as array string array arcs inside this I'm writing uh running running in main method if I put uh this parenthesis that means method so uh what will happen you know how the execution starts all of these things will not they will be suspended like this only execution starts line by line in inside main method okay first this will get printed after that you will have to call the methods to print okay which method you want to print first my dog will my dog will bark so the name of the method is bark just copy this bark come over here and termination semicolon so bark method will execute after that you just write eat method uh no no after that my dog would like to play he is barking just to go out to play he will play after that once he has played he'll come home and he'll eat something and then he'll go to sleep okay so these all things it will do one by one first this line will get executed then this method will get executed then this method will get executed then this method will get executed okay line by line control will go execute it will come back okay now after this if you want to print what is the name of the dog what is the age of the dog you see uh how do I do system. out. println I'm writing name of the dog is I'm just writing plus Oreo okay uh what I'm write okay I'll just put it over here what is this is static okay this is global variable you'll get to know a little later okay now uh what I have done is some string value okay and over here I have given certain space plus whatever the variable name is there okay now that will print okay same thing if you want to do once again system. out. printer and I'm writing age of age of Oreo plus plus age okay so whatever this variable name is there right I'm just trying to put it over here I'm just putting putting plus so what will happen you know this is a string plus means it will not do the addition right uh B plus C it will not produce u g okay uh or or sorry like uh c plus c it will not give you answer as F right c means three uh 3 + 3 means six means F no it will not do like that so age of Oreo is not a number so this is a string and uh this is number so string and number addition cannot happen so this plus sign will try to join them okay getting it now let's try to execute it everything I have written in main method let's try to execute it right click over here try to run as and you will see the option called Java application run as Java application something will get to print something has been printed over here you see this is known as console and in this console running in main method me parenthesis means method okay Oreo barks first I called bark and first I had called bark so Oreo barks and second I had called play so Oreo plays third I have called eat so Oreo eats and two things I have uh printed also name of the dog is Oreo from the variable and age of the so this is how the programming works okay line by line This is the execution sequence these all things you will get to learn in our programming um Java certification programs not only this let's understand what is the Journey of your learning okay first you will be learning about the introduction means Java fundamentals okay what all things would be there into it uh what are Java fundamentals what are data types what are variables what are literal means what are values okay what are print statements how do you use that and after that data handling and functions means functions means methods and all okay these are things you are learning and Hands-On each time whatever the topic you are learning for that you will have you'll be having handson okay next next topic is going to be objectoriented programming okay there are a few topics in objectoriented programming that you should learn not only for Java okay One More Concept that people come across that okay once I have learned Java then I will go and Learn Python no uh I am just stating that whatever the program language you are learning okay once you learn one programming language to the core okay every programming language will have two parts okay Theory and practical means means programming so Theory everywhere 80% it is going to be the same I'm just taking this window roughly 20% it is going to be only the syntax related changes only syntax related changes but whenever you will be doing programming right whatever the logic you are putting everywhere come me whatever the language you are using JavaScript Java python C Ruby Pearl anything everywhere everywhere programming is going to be the same means logic is going to be the same so once you are learning one programming language you will be self-reliant self-sufficient to jump onto any other programming language only for these 20% thing which is syntactical thing within 2 to 3 days you can jump onto any other programming language that's why I say learn any programming language to the core okay I have been a guest lecturer in well Institute of Technology there also I uh was asked this question so I stated the same thing okay so objectoriented programming is common in all of these programming languages okay getting now fourth number topic is seret okay you will learn seret and you will also learn about the packages and multi threading okay all right now after this multi- threading concept uh in mobiles also multiple applications runs uh in your uh mobile that also is multi-threading concept only okay Java Collections Java collection is super duper important topic from the interview point of view not only that Java collection is a data structure actually how do you put your data how do we save how do you save your data okay that is important so Java Collections talks to you about that okay now handson uh then jdbc how do we create a connection with the databases okay those all things we are going to learn and after that you are going to learn very popular framework that is hibernate all right then you'll be superhero because from the ground from the scratch you have have started and this is a road map you have been through and you have learned all the programming Concepts which are required all right okay spring hi bernet sallets okay spring AXS and design patterns design pattern is not only common to the development team it is also common to the testing team design pattern is something okay you have just learned everything okay if Carpenter if Carpenter learns how to use the tools uh do you think uh he'll be able to bring uh he he'll be able to do the or he'll be able to carve Taj Mahal or he'll be able to carve whatever uh the temples are there in India no right what is the design pattern how you are trying to put all the like if you have 3,00 like if you have 100 files how will you keep those file so that your efficiency and efficacy is also not going down okay and and just think about you all of you might be driving your car in your car whatever this um gear box is there okay if you are not driving uh this car um automatic car you might have you you would have seen you will have I mean I should say you you would have seen the gear okay without looking at gear all of you might be able to change the gear it is gear number two gear number three gear number four okay you you always will be f focusing on the road right have you or or do you drive it like this uh okay I doubt you might have got the driving license uh while changing the gear do you closely look for 20 seconds to the Gear or 4 seconds or 5 Seconds to the gear then you swiftly shift the gear P gear or you change the gear no right because it has been created in such a way okay that is design pattern okay that is design pattern so this is the journey of our Java course all right guys thanks for joining the session I hope your time has been valued bye-bye