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In this lecture, we'll run with you.

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What comments are and what type of comments are available in Java source code and apart from that,

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we'll talk together regarding Deep's and best practices while using comments.

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First of all, let's come up with a common definition here.

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The Java comments are statements that are not executed by GBM.

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The comments can be used to provide information or explanation about the variable method class or any

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statement.

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It can also be used to hide program code temporarily.

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Comments often used to live so-called to do comments mentions.

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Do not forget to restructure code or to add something in the future.

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There are three types of comments in Java.

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Single line, multiline and Javadoc.

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Let's take a closer look at how comments are looked like in our clip's workspace.

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Here is our hello world application, which we all know, let's add a single line comment right after

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console output.

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That was to do at more court here in the future.

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By the way, in the clips, if you want to find all to do comments in your code, just go to window

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shoyu desks.

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Here it is.

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Just don't forget to save your file before that eclipse passes all to the comments and lists it here.

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I used this too many times.

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There is a hotkey for single line comment.

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For example, you can comment this code line by pressing control plus slash and uncommented in the same

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way.

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You can select few lines, for example, the whole method, and call it the same way with hotkeys.

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And uncommented, if you wish, with the hotkeys now let's create multiline common type slash asterisk

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and enter.

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You see how Eclipse helps us to write Multiline Command, you can type something like this, please

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do not remove this quote.

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And now let me show you, Javadoc, the first thing you should know about Javadoc is that this type

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of comments can be converted to nice looking TAMAO pages in JDK.

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We have Javadoc program which generates these e-mail pages out of our source code.

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Let me show you example.

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Here is official javadoc of string class.

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You can see class description, constructor, fields' methods.

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All of them are clickable.

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For example, let me click here.

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You can generate the same documentation.

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Let's learn how to do this.

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Let's create Java documentation for our main method.

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Slash Nebel Asterisk Enter.

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And here your comment goes the entry point to that program.

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You can see the stack there, it is used to add parameter to parameter section in Javadoc, I will share

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with you more tags to learn in the homework section.

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Meanwhile, let's add clarification here.

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Input arguments.

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Let's also add Javadoc to our class.

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You can see Ostertag here, I will leave the next comment here.

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Hello, world application.

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Now we can save the file, we are good to generate javadoc to generate javadoc from Eclipse Project,

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generate javadoc you configurations you can configure output folder for your documentation.

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I will leave default settings here and will press finish.

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Now, you can see that dog directly appeared in our project, let's expand it, find index, dot Ashton,

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nail file and open it.

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You can open it in any browser or you can just use built in Eclipse browser.

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Right.

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Click open with Web browser.

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And here we have our documentation, congratulations.

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This is your first documentation to your first program.

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You see our class here.

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Here's our class description.

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Orser Constructor's Method's, here is our main message description.

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And here's our arguments description.

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Let me share with you tips and best practices of using comments in Java.

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The first thing you need to remember in case you want to comment, chunk of code to hide this code,

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just remove it if you don't need this code.

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That means you don't need this code.

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I faced with this so many times when developers comments there or others code and leave it just in case.

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Be smart, you will learn how to use version control systems.

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And believe me, there is no such cases when you need to leave code just in case, especially when you

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have a version control system, because this will end up having a lot of comment at code, which nobody

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knows what is it for and you won't be able to support it.

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My next advice always remember that comments require maintenance.

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You need to keep them up to date and relevant.

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Don't forget about this.

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I'm trying to be a good tutor and I am saying that right in Javadoc is great.

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But also I have to prepare you for real life.

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In real life.

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You would notice that not all developers write comments.

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Why?

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Because sometimes they are not needed because you have live documentation, your unit tests in your

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test data as you change your code.

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We'll discuss in later lessons Giggie approach and goals of unit testing.

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But for now, just remember, in case you have solid unit test code coverage and you follow Jawa naming

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conventions and choose meaningful names for variables and methods, sometimes javadoc in this case is

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redundant so they will learn what comments are.

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Now we also know what types of comments we have in Java.

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You saw how to generate Javadoc from the source code and also I shared with you tips and best practices

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of common usage in real life.

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And your homework created Javadoc for your Hello World application and generate documentation from your

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source code.

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Also, during the lesson you saw only a few javadoc decks.

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There are no need to go over each of them because most of them self describing, you know, already

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how to use them.

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Just take a look through this table to know what other text you can use.