I have two modules:
module 1: builds as .tar.gz with assembly plugin (type declared as 'pom' in its pom.xml)
module 2: needs to depend on the .tar.gz from the module above but always pulls the pom from the nexus instead.
Is there any trick? I see my .tar.gz on my Nexus correctly, it's just module 2 never goes for it, always just downloading the POM.
I finally found the issue. If I look in the metadata of the nexus (maven-metadata.xml)
I see my .tar.gz with a classifier tag from the maven assembly plugin id (the one from the external assembly xml).
I had this in the dependency plugin config, but not lower in the actual dependency section of my pom. Once I also added the classifier tag here, it all works as expected.
Related
I a maven rookie and am wondering how to get a binary jar file if it is not already in the repo. Specifically i'm in need of: jackson-dataformats-text-2.13.0.jar. Do I need to build it myself? I'm used to creating a project and marking a library as a dependency and seeing the jar downloaded into my .m2 cache but all i see in my cache is:
jchan#jchan-Z170N:~/.m2/repository/com/fasterxml/jackson/dataformat/jackson-dataformats-text/2.13.0$ ls
jackson-dataformats-text-2.13.0.jar.lastUpdated jackson-dataformats-text-2.13.0.pom.sha1
jackson-dataformats-text-2.13.0.pom _remote.repositories
Can someone advise how I am to get a built version of the jar from maven central?
We are still maintaining our ant build and I need the jar file for this. (i know i know, ancient stuff but team is not ready to port just yet).
parent pom don't contain jar file
This is the reason why no bundle link is present on the official public maven repository https://mvnrepository.com
The maven dependency is not a jar, is a parent. So the extension is: .pom which is just a plain pom.xml
Parent dependencies don't contain compiled class like .jar.
In your specific case, there are another dependencies who contains jars:
https://repo1.maven.org/maven2/com/fasterxml/jackson/dataformat/jackson-dataformat-yaml/2.13.0/
https://repo1.maven.org/maven2/com/fasterxml/jackson/dataformat/jackson-dataformat-xml/2.13.0/
advice
Check what classes do you need on your ant project and search if exist a jar (with the classes you need) on https://mvnrepository.com
Another option is to get all the dependencies from pom :
https://repo1.maven.org/maven2/com/fasterxml/jackson/dataformat/jackson-dataformats-text/2.9.0/jackson-dataformats-text-2.9.0.pom and download them into your ant project. In theory is the same of add the parent pom in a maven project
I would like to distribute the main artifact sources (main Java and tests) of a multi module project as a simple - standalone - Maven project.
The easy parts of this can be implemented using the maven-source-plugin. This also is able to include the POM in the generated source code jar. However, this is the artefact POM, which refers to the parent POM which is not included in the jar.
Other than creating the POM manually, is there a way to generate a minimal POM which contains the dependencies (extracted from the artifact POM and its parent)?
If you create the POM with the flatten-maven-plugin, all parent relations are resolved and you get an equivalent POM without the unnecessary parts.
https://www.mojohaus.org/flatten-maven-plugin/
I am trying to understand relationship between artifact, group, class definitions.
For example, I've seen the following artifact declaration:
<groupId>org.seleniumhq.selenium</groupId>
<artifactId>selenium-java</artifactId>
<version>2.53.0</version>
Is there a file associated with this artifact?
Is this enough information to pull down the file down when building your Maven Project?
Where is it getting the file from? Is it getting it from selenium, or does Maven house these artifacts, and it is getting from Maven?
Where exactly is it downloading the artifact from?
What's in the artifact file? Class definitions? Multiple classes can be defined in there, right?
Maven seems to be making a jar file. Is it compounding all the classes into that file?
Also, how is artifact file different from JAR file and can you make your own artifact file?
Is there a file associated with this artifact?
Yes, what you have posted is known as a coordinate. It references a jar named selenium-java that is in the group org.seleniumhq.selenium.
Groups, identified by the groupId component of the coordinate, are a way of namespacing artifacts within maven to prevent naming collisions.
This coordinate says that the project has a dependency on version 2.53.0 of a maven artifact named selenium-java in the group org.seleniumhq.selenium.
Is this enough information to pull down the file down when building your Maven Project?
Yes, the coordinate is how the artifact is located within the maven repository and is enough information to locate and download the artifact when building a maven project.
Where is it getting the file from? Is it getting it from selenium, or does Maven house these artifacts, and it is getting from Maven?
Where exactly is it downloading the artifact from?
Where the file is retrieved from is based on your maven configuration. By default maven will first check the local maven repository on your machine to see if the artifact has already been downloaded. If not, it will then check Maven Central.
You can also host your own maven repositories using tools such as Nexus or Artifactory that can mirror repositories on the internet such as Maven Central as well as store artifacts you create yourself that you do not with to share with others.
What's in the artifact file? Class definitions? Multiple classes can be defined in there, right?
An artifact can be any type of file. In the case of the selenium coordinate above the artifact is a jar file. There will also be a pom file associated with that coordinate that explains all of the dependencies of the selenium-java jar.
http://search.maven.org/#artifactdetails%7Corg.seleniumhq.selenium%7Cselenium-java%7C2.53.0%7Cjar
Maven seems to be making a jar file. Is it compounding all the classes into that file?
You can build normal jars or fat jars with maven. By default maven will build a normal jar. If you wish to package all of a jars dependencies within it (i.e. fat jar) you need to use a special maven plugin.
http://maven.apache.org/plugins/maven-shade-plugin/
Also, how is artifact file different from JAR file and can you make your own artifact file?
Artifact is a generic term used to describe anything you can store within a maven repository. Maven repositories can store many different types of files. In the case of this coordinate the artifact is a jar file.
I made a Maven project and declared packaging as war.
<packaging>war</packaging>
But this returned an error,
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-assembly-plugin:2.2-beta-5:single (make-assembly) on project WaterDealer: Execution make-assembly of goal org.apache.maven.plugins:maven-assembly-plugin:2.2-beta-5:single failed: For artifact {ArtifactName:ArtifactName:0.0.1-SNAPSHOT:war}: An attached artifact must have a different ID than its corresponding main artifact.
But when I removed packaging declaration, everything worked just as expected.
Is there any specific reason for this happening? Why did declaring packaging type return an error An attached artifasct must have a different ID than its corresponding main artifact. ? How are they related?
I went through POM reference from this link Maven POM reference but did not find the information very useful.
the error is from the assembly plugin which is not directly related to the packaging.
the packaging defines the type of artifact produced by maven (in general: one pom.xml one artifact - there are exceptions to this rule, e.x. sources jars or javadocs).
the default is "jar". so if you do not specify anything maven will create a jar file.
The other available values for packaging should be a bit self explaining?
The error might be simply the name that results. So packaging jar will create a jar file, "war" will create a war file and so on. If your assembly plugin creates a war file that may conflict with the war created through the pom.xml
The packaging defines some of the binding which are done. This means if you decide to use packaging war it means to run maven-war-plugin in the package phase. This can be read in the appropriate documentation.
The question is why you using maven-assembly-plugin in a war module and apart from that why using such an old version. Take a look on this site which shows the uptodate versions of the plugins:
http://maven.apache.org/plugins/
On mvnrepositry, when you search for a certain module, there's a link to download the binary. For some versions it has a pom.xml file available for download instead of the jar. What are you supposed to do with that pom.xml? It seems like if I specify a version that does not have a downloadable jar, but instead downloadable pom.xml, my maven build will fail. Is what I'm seeing correct?
Modules that only have pom files are maven modules with pom packaging. They are used to aggregate multiple modules into one unit. You can use such a module as a dependency for your maven project. Maven will download the pom file, analyze the dependencies included in that pom file and download those & add it to your automatically.
Even modules that have jars (jar packaging) have a pom file associated with them. This pom file defines the other dependencies that are required for using it. Maven will automatically process and fetch those dependencies (transitive dependencies).
This makes specifying and managing dependency for any project. You will specify the top level modules that your projects directly depends on and other things required will automatically figured out and downloaded. It also makes it easier when you have upgrade to a new version - all the transitive dependencies will get upgraded automatically.
One of the reason that cause this is because of licensing issue.
License for such JARs prohibit public redistribution in such approach. So someone provide only the POM so that you can get the JAR yourself and install it to your local maven repo/ internal repo, together with the POM provided.