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In Maven, an entire project's configuration can be encapsulated in the file named pom.xml. POM stands for "Project Object Model". This video discusses the high-level details of what most POMs will contain.
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Now, that we're gonna be peeking into files and write any a bit of code,
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it's time to switch to an IDE.
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I'll use IntelliJ IDEA, okay, excellent.
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I'll open this project panel and
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then, I will open palm.xml, there it is.
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As I said in the last video, POM stands for Project Object Model.
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And this file represents a one stop configuration for the entire project.
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As you can see, it's an XML representation of the Maven project.
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The root node of a POM will be this project element
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followed by the model version element.
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Which for anything using Maven 2.0 or higher,
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the model version will be 4.0.0, okay?
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Next following this model version is a group of four elements that define what
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are called the Maven coordinates.
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That's the group ID, artifact ID, package, and version.
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If you've used other dependency management tools,
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you've have to reference these coordinates to use a third party library.
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These categorize and identify the archive that this POM
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will produce on a repository like Maven central.
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Let me show you an example of what I mean.
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If we need a third party library, that helps us examine file metadata,
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like file types and the dates that they were created.
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We might use the Apache Tika library.
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Now, I can go to search.maven.org and search for Apache Tika.
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And if I scroll down a bit towards the bottom of the page, I see tika-core.
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And upon clicking on it, I will see the group ID,
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the artifact ID and that version right there.
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And even all the way over to the right, I see this jar, okay, back to IntelliJ.
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This group ID here is a unique identifier for a business or organization.
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Usually, in a form similar to Java package naming, in our case, com.teamtreehouse.
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The artifact ID, is an identifier unique within the group.
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And helps pinpoint the exact project within combat team treehouse.
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In our case, it is file-spy skipping to the version and
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this one is fairly self-explanatory.
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What version of file-spy will the created artifact represent?
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A quick note on SNAPSHOT, whenever you see that on an archive,
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that means that this project is a work in progress.
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It is not a final release, yet.
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Now, speaking of that artifact, if we backtrack to the packaging element,
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we'll see that ours specifies jar.
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And this packaging element specifies the kind of archive created by this build.
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When put together, the artifact ID, version, and packaging
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elements all combined, will represent the name of the generated archive.
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We will see later on that our archive will be named file-spy-1.0- snapshot.jar.
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Okay, these next two elements, a name and
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url give the project a nice reader friendly name.
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As well as a url for the Maven project itself.
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And following that, we see this dependencies element.
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In this element,
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we'll specify all the external libraries that this project depends on.
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There is one in there by default and that is this junit library.
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We'd want this library if we were writing unit tests.
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Which in a distributed Java application, we definitely want to do.
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Okay, let's take a break here before returning to these dependencies in
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the next video where we'll start coding our application.
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And in doing so,
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we'll lean on a third party library that will add to our POM file.
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