What is Java and Why Is It Special?

Hello my friend, today I will tell you what is Java, what is programming language, what is Java virtual machine, what is a compiler and many other things like that. These are basics and this lesson is very, very important in order to understand anything in any language, not only Java, if you want to understand programming, you have to watch this lesson. After this lesson, everything is going to become clear. So what is Java? Java is a programming language that we use to talk with our computers. Our computer is talking in a bit different language than we are talking. I'm talking in English language right now and you understand me pretty well. But our computer likes things like that, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1. Why? Because these are electric impulses and they jump from 0 to 1 and that's how computer is interpreting everything that you see right now. It interprets the sequences of 0 and 1. It would be very hard for us to write programs like that. Imagine writing things like that. That would be horrible. That's why we have got something what is called programming languages that are having syntax that is easy to understand for us. It is not as easy as, for example, right now, English, but it's going to be easy when we learn the rules like we learned, for example, for English or another language, and we just going to be able to talk. For example, we can write later something like integer B and it means, hey, I want to save in the random access memory, so in the RAM, a place for the integer. So it means I want to save a number somewhere. I want to find a place like that. And this thing would mean I want to reserve something for computer. It needs to be also changed to 0, 1, 0, 1, 0, 1. And the process of changing this into 0, 1, 0, 1 is called compilation. So programming language is something that is understood by us as syntax. This can be easily changed into 0 and 1. And why did I put so much effort to tell you what is a programming language? Because in Java, the process of compilation is a bit different. It's very hard to understand for people new to Java. And some people do not even understand it after writing programs in Java for many years. So what's going on here? Normally, let's, for example, see here a programming language like C++. When you write a code, imagine here we have got some kind of code. So we have got something like that in B or other things like that, or something like that in Java or whatever. We have got some kind of code here. And this code is going to be changed by something. What is code? Compilation. So we can write here compilation. So this thing is going to be changed into the 0 and 1. 0, 1, 0, 1, 0, 1. This is called machine code. It's going to be executed. There is small problem in the C++ solution, because there is Windows, there is Linux, there is Macintosh, Android, and other things and other platforms like that. The problem about it is that when you make that compilation, we changed this code into the 0 and 1. It needs to know the processor that is going to execute the instructions here written in that code. And because of it, when we compile it on, for example, Windows, it's going to be able to run only on Windows. So you have to later compile it also on, for example, Linux. And the problem is also that on Linux, you can have libraries that are not, for example, on Windows, or you can have on Windows libraries that are not available on Linux. And then you have to write code many times. Wow. This is horrible. If you want to support many platforms. The cool thing about Java, and that's why it's one of the most in demand and highest paying programming language, is that the slogan of Java is write once and work everywhere. Why and how did they manage it? Java is doing something like that. We have got a code like that. We have got a process that is going to change this code into something, what is called byte code, byte code. So it is something like between the code that we have got here and that we have got here, 0101. That byte code is not going to be useful for us humans because we cannot read it, but it is very nicely written code that is going to be interpreted by something, what is called Java virtual machine. This is a program. This is an application that you can install. This is a platform that you can install on any computer, on Android, on Linux. This thing is going to change byte code into 0 and 1. And that's cool. It's going to change this thing into byte code that can be interpreted on any platform. That's why it's so awesome. But you have to also remember that you have to install this Java virtual machine. So without the Java virtual machine, you're not going to be able to run it. We're going to install later something like that. That's called NetBean. It's an editor that allows you to write code in place like that. And this code is looking like that. Public class Java application. We're going to talk what is public meaning, what is class and other things like that. We're going to click play, like here, and it's going to compile this thing. So this code, the programming language, into something, what is called byte code. And then the byte code is going to be run by Java virtual machine in time, just in time. You might be like, now, hey, this must be very slow. And you are right. It is slower than the C++ solution. You have to choose this or this. You want spit or you want to support all platforms. But it's not also very, very slow because for example, when you have got a code that looks similar, then it's going to create in the byte code, a special instruction that is going to make it simpler. It's also not going to compile all your code. If some of the instructions are rarely used, if something is going to be used very often, it's going to even sometimes run faster than in C++ because it's going to create special connections that are going to make run things that are run very often. So it really depends on situation. Java is most times slower. Sometimes it might be even faster than C++, but the truth is that you shouldn't worry about it because our computers are faster and faster each day. If you want to write applications, desktop applications, or for example, Android applications, things like that do not matter. If you have to write drivers where speed really matters, then C++ and other languages that are like C++ are very important. Remember that even games are written in Java. For example, popular game like Minecraft was created in Java. So you have to know that there is a process that is called a compilation here. So the compilation is changing code from one type of code to another code. And compilation also checks if you made some errors. So if I do something like that, as you can see, and when I click play, hi, there are some errors. It helps you debug your code. So you can find bugs, the problems, the errors in your code. We'll talk about things like that also later. We will install the IDE, integrated development environment, so that this editor that has got lots of useful tools, we'll talk about all these things later. In this lesson, you right now know what is programming language. The programming language is used to create programs, so instructions that are going to be executed after changing it into the machine code by our computer. So we are requesting computer what to do. It's like forcing him to do, it's commanding him, hey, do something, go into the system and then out of it and then print a line, like for example, hello world. And when I click play, as you can see, we have got here, hello world. We'll talk about why here is a dot, why here is a public, how these rules work with each other in next lessons. Remember that if you have any questions, just ask me. I really love helping other people. That's all in the lesson. Thank you very much. Thank you. Thank you. Thank you. Thank you. Thank you. Thank you. Thank you.