maven is downloading every dependency when doing ' mvn clean package' . along with the dependencies , its also trying to download maven-metadata.xml with each dependency. In my system maven is not able to download this maven-metadata.xml . Does anyone know , what is this maven-metadata.xml ? and the possibilities of download failure ?
maven-metadata.xml is required only if you do not know the group id, artifact id and version information. Please post your pom.xml here. There could be some issues with it. Also, ensure your local Maven repository (on Windows, D:\Documents and Settings\user.name.m2\repository) contains the needed dependencies.
For example, log4j can be considered correctly installed locally only if the repository\log4j\log4j\1.2.12 folder contains a Jar file and POM file. When these two are present and you mention artifact id, group id and version correctly in pom.xml, Maven will pick up the jar file locally and will NOT download each time you build.
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 want to use a project called projectA that I have in a maven repository as dependency of a projectB.
The mvn deploy of projectA is successful (I can see in the repository the projectA-0.0.1-20190902.072951-1.jar, projectA-0.0.1-20190902.072951-1.pom and maven-metadata.xml files), but when I specify the dependency in the pom.xml file of projectB, the project works but it downloads two JARs of projectA from the repository:
- projectA-0.0.1-20190902.072951-1.jar
- projectA-0.0.1-SNAPSHOT.jar and the same issue for every file downloaded by the dependency to this project.
I think that only one JAR is necessary, and I don't know what I need to put maybe in settings.xml or in the pom.xml file of any project to get only one JAR when the dependency is downloaded.
Thank you so much for your help!
In the past it was possible to tell Maven to deploy Non-unique Snapshot Deployments but in Maven 3
... snapshot artifacts will always be deployed using a timestamped version
So:
the files with the timestamps are the one you have deployed to your remote repo (mvn deploy ...) and then downloaded from there as dependencies
the ones with -SNAPSHOT are the result of the local builds (install goal)
If your concern is download traffic - that is not an issue. The -SNAPSHOT ones are not downloaded.
If your concern is disk space then you can have a cron job or use something like Build Helper Maven Plugin to remove old version artifacts from the local repository.
I have been looking for a dependency for csjdbc.jar in Maven repository so that I can build my app using maven and retrieve that jar on the fly. However, I cannot find a dependency in Maven repository related to that jar. Can anyone help, please?
Hopefully you have already resolved this issue.
csjdbc.jar is not listed in maven repositories. If you have composite software installed you can copy the jar from
~\Composite Software\CIS 6.1.0\apps\jdbc\lib
directory to your local machine's maven repository like below with proper versioning:
C:\maven\repository\composite\csjdbc\6.1\csjdbc-6.1.jar
(I have 6.1 jar)
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.
Now, i have a project which runs fine on my windows computer. But after I copied it to a linux computer, when compiling it reports following error:
Failed to execute goal on project alert: Could not resolve dependencies for project com.cloud.ras:alert.
The POM for com.external:commons-logging:jar:1.0.4.1 is missing, no dependency information available
The POM for com.external:freemarker:jar:2.3.4 is missing, no dependency information available
The POM for com.external:log4j:jar:1.2.14 is missing, no dependency information available
The POM for com.soa.lib:eBoxServiceCommon:jar:2.5.3 is missing, no dependency information available
but i have copied these jars to the maven repository. And can anyone give me a help?
You should NOT copy JARs in the first place. That's Maven job to resolve the dependencies for you.
It would be helpful if you explain the reason why you need to use your own groupId e.g. com.external in the first place i.e. commons-logging is from Apache but you use com.external as its groupId.
If you really insist on wanting to use your own groupId, at least download the JAR and install it using Maven. See here:
http://maven.apache.org/guides/mini/guide-3rd-party-jars-local.html.