Maven - Identifying the source pom file of a dependency - maven

I have a situation where in my EAR file I have 'N' number of JAR files[modules] present. In these JAR files, there are certain artifacts which are duplicate. By duplicate, I mean the artifact name is same but with different versions.
Ex:
adapter-base-59.0-20141219-311675-3.jar
adapter-base-60.0-20141223-678915-68.jar
I would like to get help on how to find the source pom file location for these JAR files.
Any help on this is highly appreciated.
Regards,
Deepan

that might be a bit painful but the dependency can be in a parent pom.xml, a transitive dependency or a profile. Profiles can be in a settings.xml as well.
What I would do is execute mvn dependency:tree on the pom.xml where the dependencies are copied and then search where it comes from. Then follow that path.
It is a little weird you have the same jar twice with a different version. Usually maven takes the first one (or closest one) it find. So adding the correct version to your pom.xml has a distance of 1, that would always win - any transitive dependency will have a greater distance.
It might be the dependency uses a different groupId and maven cannot detect its the same artifact.
You could also try to open the jar files - maven usually adds some information into the META-INF directory (if you're lucky and the jar was release with the maven-release-plugin).

Related

Why doesn't the dependency contain a jar in the maven public repository https://mvnrepository.com?

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

How can I expect maven to resolve dependencies required by the child jar?

I have a parent project(has its own pom.xml) in which I import the child project as a jar with its own pom.xml.
In the parent pom.xml I have specified my child jar as a dependency - this gets resolved, but i want maven to resolve the dependencies required by my child jar.
My Use case to replicate :
When I include spring-web-mvc.jar the transitive dependencies are resolved automatically.
I have a similar requirement where I include my child.jar into a main framework project and expect the transitive dependencies to get resolved (Notw: the child.jar is not hosted it is packaged as jar and present on the local file system)
Current Structure:
Child Project:
|----/src/main/java
|----/src/main/resources
|----child-pom.xml
>This child project will be a jar as dependency in the parent project
Parent Project
|----/src/main/java
|----/src/main/resources
|----/src/main/webapp/WEB-INF/lib/child.jar
|---- parent-pom.xml
The problem:
When i create a war from parent project i want all the dependecy including transitive ones to show in WEB-INF lib.
Currently this is not happening.
First when talking of parent/ child Maven projects normaly you have your"childs" specified as modules in a common parent project which itself is beeing packed with the packaging type pom rather than make them a dependency of the parent project.
When it comes to the dependencies of your "childs" or generally "dependencies of your dependencies" those are called transitive dependencies and are pretty well explained in the official documentation found here: http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html
The resolving of those transitive dependencies is one of Mavens core strenghts and guaranteed by default unless they lead to conflicts that make the build fail.
Two things to help here are having a closer look into the enforcer plugin (http://maven.apache.org/enforcer/maven-enforcer-plugin/) and the shader plugin (http://maven.apache.org/plugins/maven-shade-plugin/) .... well and the official documentation of corse (reading the whole thing takes less than a day - then supports you further for specific topics whereas we gladly further support you too if you already have pom.xml files and you are stuck somewhere.
While the enforcer-plugin covers certain conflicts regarding different versions of the same artefacts the shader plugin will just pack everything you specified to a single jar for reverseengineering (its not the normal use case but i sometimes use it that way if i am not absolutly sure what ends in my final archives).
Also worth a look at is the dependency-plugin already available in the maven distributions - mvn dependency:tree -Dverbose will give you pretty detailed information on the resolved dependencies (and probably version conflicts).

How to download with Maven a project jar and its dependencies without checking out the sources

In one Java project, I have configured its POM so maven will generate in the target folder:
the binaries jar.
the sources jar.
the javadocs jar.
the tests jar.
In addition, I configured the POM so Maven downloads all the project dependencies in the target/lib folder.
The project is also uploaded to the Sonatype snapshots repository.
My question is: Is it possible for a user of my library to download all the artefacts mentioned above with one single instruction, without having to checkout the sources of my project first ?
I found in a question from some years ago that just distributing the POM is not enough to download a project and its dependencies.
But I have not lost hope that this could be possible to accomplish in one single step.
When you say "all of the artifacts mentioned above", do you mean:
the binaries jar.
the sources jar.
the javadocs jar.
the tests jar.
or do you mean:
all the project dependencies
Assuming the latter, then have your user do the following:
create a dummy pom.xml file
declare your library as a dependency
use maven-dependency-plugin:copy-dependencies to copy jars into desired location
Hope that helps.

What is the purpose of providing a downloaded pom.xml on mvnrepository.com

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.

maven - how does it work? Missing some some jars

I am trying to move my MyEclipes projects to maven. But of course there are problems. After creating a web priject I get missing jar files - about 5
org.springframework.security jar files e.g. org.springframework.security.ldap-3.0.5.RELEASE
show as missing in the jar build path. They are not in the corresponding .m2 directory. I un-installed ME4S, and deleted .m2, which force .me to be rebuilt on re-install, but it has the same problem.
How do I fix this?
It would be very helpful to understand how the .m2 process works - where is this coming from and how is it controlled?
I am not sure about the MyEclipse part, but this seems to be a pure maven question.
Maven (2/3) uses the pom.xml. This file describe your project. In that file you should define a list of dependencies (which can have their own dependencies and so on).
Maven read the pom.xml and build the classpath accordingly using direct and transitive dependencies.
You can use the mvn dependency:tree command to see how your classpath is built.
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