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Java Lesson 1 | Hello World


3m read
·Nov 3, 2024

This bath has 101. I'm a special guest. My name is Jake, and this will be the first of my Java tutorial.

So, the first thing we need to do, if you don't already have Eclipse, is download that. You get that from eclipse.org and then downloads. The one I'm going to be using is this one at the bottom: Eclipse Classic. Of course, I'm not gonna be downloading that because I already have it, but if you don't, download that.

So first, just going to open up Eclipse. I'm gonna make it a HelloWorld application in this one, so just letting you know. Um, so the first thing I actually need to do is File, New. We're gonna be creating a new Java project.

So this is our project, and I'll name the projects "the projects." Then, window, show view, Project Explorer, so we can see all the projects. Now, we can't just start coding in there because we don't have a class yet; it's actually where to write the code in.

So, you click File, New, Class. I'll name that class "Capital" and "MathHeads." Now I'll just double click this to make it bigger.

So now what we have is a class, it's "public class SmackHeads." In order to actually make some code to execute, we need to make a main method. What the main method is, it's what Java is gonna be executing the code from. But first, a method—what that is—is it is a list of instructions essentially.

So, like, if I had my own method for making soup, like the method for making soup would be like: cut vegetables, sauté vegetables, boil stock, something like that. So the method is the list of instructions that we're going to be doing.

To make the main method, you have to write all this. You don't really have to understand much of it right now because it's just not important, but you write "public static void main." The "public static void" is what's important because that means it's the main method. Then, capital S with "String args" brackets with nothing in them.

This you do need to understand. Now, the curly braces—whatever is in here is the body of the method, just as whatever is within these two is what's in the class, which would be methods.

To make the HelloWorld, it basically prints out "Hello World" to the console. So to do that, you type "System" with a capital S, dot "out," dot "print." Then, in parentheses, you write what you want to print, which we're gonna put in quotes because if you're just printing text, you have to put it in quotes.

So in the close, I'm gonna put "Hello space World," and you have to end the line with a semicolon. So "System.out.print" and "Hello World" and you click this little green button to compile it, and it prints "Hello World" to the console.

Now, there's also "System.out.println," which prints like a newline. So I'll show you the difference between the two. I'm going to make another print statement, and I don't know why I didn't just copy and paste this. Whatever, hi.

So now if I compile this, you see they're right next to each other. Of course, I could just, you know, put a space right here. But if I want them to each be on different lines, I would have to do "System.out.println," and that prints it on a whole nother line.

So if you wanted it to be printed on a whole nother line, use "System.out.println." If you just wanted to print it on the same line, then use "print."

So that is Hello World, and then we'll see you in my next tutorial.

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