Start a free Courses trial
to watch this video
In this video we will explore the development environment we will be using for the rest of the course, Workspaces. We will write, compile and run a command line program that will introduce ourselves.
It's not an error!
- Not to worry, the
Picked up JAVA_TOOL_OPTIONS: -Xmx128m
is not an error on your part, we recently just tweaked our setup to have more memory allocated. Don't fret that mine looks different!
Additional Content
- Learn more about the command line in the Console Foundations course
Related Discussions
Have questions about this video? Start a discussion with the community and Treehouse staff.
Sign upRelated Discussions
Have questions about this video? Start a discussion with the community and Treehouse staff.
Sign up[MUSIC] 0:00 Hello and welcome. 0:04 I'm Craig, and I'm a developer. 0:05 For this course, it doesn't matter if you have any programming experience at all. 0:07 I'll be introducing you to some very common tools available in 0:12 almost every programming language that you might encounter. 0:15 We'll be doing our exercises in Java, and I'd like you to approach this 0:19 as if you were attempting to learn a foreign language. 0:23 I'll introduce you to the rules or syntax of the language as you need it, 0:26 we will also discuss the oddities that you might encounter. 0:30 As we go through different parts of this course, 0:33 you'll start to recognize words and concepts in other parts of the language 0:36 much like you would in a language immersion program. 0:40 Just like when you're wandering around a foreign country where you're just 0:43 learning the language, you'll come across words and 0:46 phrases that you aren't familiar with and that's okay. 0:48 Focus on the topics we're covering and don't worry about the other parts. 0:52 As we're cruising along, I might ask you to ignore some things, but 0:56 I promise we'll get back to it when the time is right. 0:59 You might not have noticed it yet but there is speed controls on your video. 1:02 Please feel free to speed me up and make a pretty good chipmunk or 1:06 slow me way down as you feel necessary. 1:09 I won't take any offense. 1:14 I promise. 1:15 Also, I've added helpful links in the teacher's notes 1:16 that will allow you to learn even more, sound good? 1:19 So without further ado, let's get started with our task at hand. 1:23 Just like most foreign language classes, 1:27 the first thing we're going to learn is how to introduce ourselves in code. 1:29 So, what we'll do is we'll write out or print, hello my name is, and 1:34 then your name, to the screen. 1:38 Speaking of introductions, 1:40 allow me to introduce you to where we'll be coding during this course, Workspaces. 1:42 If you click the launch Workspaces button right next to this video, 1:47 you'll see a new browser open with our programing environment. 1:50 I'll head over there with you. 1:53 So this is a Workspace, and it's all yours. 1:56 You'll see up here that there's a tabbed interface of files that you have open. 2:00 And over here is a list of files that you have available to you. 2:04 I've gone and created a file and 2:07 got it all set up with a nice starting point to begin writing our application. 2:08 It's called Introductions.java. 2:12 Let's open it up and take a peek. 2:13 I've left a note or a comment right here. 2:18 Comments in Java start with two forward slashes, 2:22 everything after the slash was ignored by Java. 2:25 So they're used by programmers to explain what their code is trying to accomplish in 2:27 clear English or to leave notes for other programmers. 2:31 Now one goal of programming is for your code to be as clear as possible, so 2:34 that it doesn't require comments. 2:38 However, as we're getting started here feel free to leave comments whenever you 2:39 want to remind yourself of what it is that we're attempting to do. 2:43 Now, remember how I warned you that you'll come across words or 2:46 phrases that you aren't familiar with and that I might ask you to 2:49 ignore some parts of code until later, we're at one of those points. 2:52 Every Java program has some setup that needs to happen and for now, 2:56 I've done that for you. 2:59 But don't worry about understanding most of the pre-written code that's on 3:00 the screen, it's just the setup that we need to do to start writing our own code. 3:03 However, the one bit of code I've written that I want you to take a closer look at 3:07 is this line right here. 3:11 But don't worry exactly about how this code works. 3:14 What you need to know is that it creates a Java object, which we'll talk about later, 3:17 which has a method that allows us to write out 3:21 text to the terminal which is down here. 3:23 I'd like to take a quick break and already acknowledge, as well as remind you that I 3:26 just threw out a mouthful of new terms like objects and methods and like I said, 3:30 don't worry, we'll cover them in much greater detail in the following course. 3:34 But for now, I just want you to continue immersing yourself in this language. 3:38 I'll explain the concepts when they're important to the task at hand. 3:42 So like I said thanks to the setup I've done, we have access to the console object. 3:45 We can use this console object to print text to the screen. 3:50 Objects like console have methods that let them perform actions, and 3:53 the action that we want to do right now is print some text to the screen. 3:57 Console's method for printing text on the screen is called printf, so let's use it. 4:01 First we'll type console, and 4:07 then a period to access its methods, then the word printf. 4:09 We're gonna call the method by doing open parenthesis. 4:14 Now we're gonna do double quotes and write the text out that we wanna write, so 4:17 we're gonna say, hello my name is Craig. 4:21 We're gonna end the double quote, and then we're gonna end the parenthesis and 4:24 then we're gonna put a semicolon to signify that the statement is complete. 4:28 You might have noticed that as I edited the file there's a little dot up here 4:32 signifying that the file has been edited. 4:36 I'm going to go ahead and I'm going to save from the file, 4:38 I mean I'm going to click File, and I'm going to click Save and 4:41 you'll notice that in the future you can use Cmd+S or Ctrl+S on a window. 4:43 Okay, so let's see our code in action. 4:48 Now, Java is a compiled language, 4:50 which means that we have to run a compiler program to turn our human readable Java 4:52 code into computer readable code before we run it. 4:56 So let's compile our introductions program. 4:59 To do that at the console, we type javac and 5:02 then the name of the file which is Introductions.Java. 5:07 Java C is short for Java compiler. 5:14 So this line is telling the Java compiler to convert or compile 5:17 the code in the file Introductions.Java into an executable file. 5:20 So I'm going to press Enter. 5:26 And if we take a look at the files in this directory using the LS command, 5:29 see that there is now a file called Introductions.class. 5:33 By the way, I should mention here that LS stands for list, and 5:39 it allows you to list files in a directory. 5:42 We're gonna use a few terminal commands on this course, and 5:45 I'll teach you everything you need to know for it. 5:48 But if you wanna learn more about using the terminal, check out our 5:50 course called Console Foundations which is linked in the teacher's notes. 5:52 Now to run our program, we simply type java Introductions. 5:56 Now notice the command that I type here is java, not javac. 6:04 Java runs the program it only needs the name of the class, without the extension. 6:09 Javac required that .java, and Java does not. 6:14 So I wanna press Enter. 6:18 And here on the screen we see our output, the introduction. 6:20 Great job. 6:24 We now have our first compiled program. 6:25 You've been learning a ton. 6:28 Before we move on and learn even more, 6:30 let's do an exercise to review some of the things we've learned thus far. 6:32 Before we get there, let me just remind you that there is a community that you can 6:36 and should lean on while going through this course. 6:40 If you have questions, it's likely someone else has them too and 6:44 has maybe even answered them. 6:47 Learning how to ask questions and 6:50 find answers is in my personal opinion the best way to learn anything. 6:51 If you're coming to this course with some Java experience, 6:56 you might have used an IDE or Integrated Development Environment. 6:59 Now those are a set of tools which greatly simplify the development 7:03 process through code completion and many other bells and whistles. 7:06 As handy as IDEs are, 7:11 I'd like to request that you still follow along in the Workspace. 7:13 As I think there's benefit in learning and gaining confidence in doing things 7:17 all by yourself and removing some of the magic of that IDE. 7:21 We'll go over IDEs in a future course when the time is right. 7:24 Okay, now back to that exercise. 7:28
You need to sign up for Treehouse in order to download course files.
Sign upYou need to sign up for Treehouse in order to set up Workspace
Sign up