Once I change the repository url and I want to test how this center downloading jars (in local repo I have downloaded jars and I want to delete those jars and restart download).
Does any maven plugin or command support this?
I think you need:
mvn dependency:purge-local-repository
See Purging local repository dependencies
Related
I would like to configure a nexus repository to only manage jars that I install. Right now it also retrieves jars from maven central and stores them in the repository. I don't want that to happen.
Can anyone point me in the right direction how this can be achieved?
When you say to store the "jars that are installed" , if you are referring to the artifacts being created by your project, you can have a hosted maven repository snapshot/release and use maven deploy plugin to upload it on to your nexus repository.
You can either create a profile in your pom and activate in your install it on mvn install phase to upload the artifacts to your nexus repository.
I have a Maven project that works just fine.
In order to triage an issue, I manually patched a jar to add debug logging and then copied it to the local Maven repo directory. I made subsequent changes to the jar file to add more debugging and did a mvn install:install-file since that seemed more "official".
Note that I did not change the coordinates at all (I know that artifacts are meant to be immutable, but I did not want to change pom.xmls).
My question is: when (if ever) will Maven overwrite this patched jar with the one in the remote Maven repository which is considered the source of truth?
There are only three scenarios in which that jar can be overwritten:
If you delete the jar from your local m2 repository, it will be downloaded from the remote repository the next time you build your maven project.
If you build your maven project with '-U' option. Doing this will force maven to update the dependencies from remote repository.
If you perform an mvn install on the same artifact(updated code) with the same version.
I have added a repository to download artifacts and I have seen maven using that repository to download artifacts, but only for particular artifacts of that repository maven tries to download from mvn central repository. When I chek that artifact on added repository it's available. What could be the issue ? In which situations maven tries to download from central repository ?
Specific issues is highlighted in ,
Magnolia Demo project mvn build failed due to not able to fetch magnolia-setproperty-maven-plugin
All the Maven dependencies are first downloaded from your local repository, then if they are not found, Maven will try in any remote repository that you define in your POM file or the settings.xml and for last it will try to download from Maven Central.
I am reading up Maven - The complete reference and came across this
Maven assumes that the parent POM is available from the local repository, or available in the parent directory (../pom.xml) of the current project. If neither location is valid this default behavior may be overridden via the relativePath element.
What exactly is meant by local and remote repository for a Maven installation and a project?
A local repository is a local directory structure that caches artifacts downloaded from remote repositories, or those that are manually installed (eg from the command line option).
A remote repository is a web service (defined by a URL) that contains versioned artifacts. This might be as simple as an Apache server, or a full-blown Maven repository, such as Artifactory, that allows uploading, permissions based on a user directory, etc.
http://maven.apache.org/guides/introduction/introduction-to-repositories.html
By default, Maven will source dependencies from, and install dependencies to, your local .m2 repository. This is a precedence rule, and your .m2 acts like a cache where Maven can source dependencies before downloading them remotely. You can bypass this behaviour like so: mvn -U ... (see mvn --help).
Your local .m2 can be found under C:\Users\{user}\.m2 on Windows, or /home/{user}/.m2 on Linux. If you do a mvn install, your project will be locally installed under the said .m2 repository.
A remote repository is a Maven repository, just like your local .m2 repository, hosted for you to source dependencies from, e.g. Maven Central.
Local repository is a repo. Into your local system, when you compile or install project all required dependencies downloaded into your local repo.
When you're working with your project, then Maven first tries to get dependencies from local. If it's not available, then Maven will try to download the dependency from a central repository.
central repo. is a online repo, which is provided by maven itself.
I have setup an in-house Sonatype Nexus repository and configure the maven to check my local Nexus instead of getting artifacts directly from public repositories.
http://www.sonatype.com/books/nexus-book/reference/config-sect-intro.html
Our project was able to download the most artifacts except one artifact in Maven central.
Here is the build error:
Failed to execute goal on project shindig-gadgets: Could not resolve dependencies for project org.apache.shindig:shindig-gadgets:jar:3.0.0-SNAPSHOT: Could not find artifact com.ibm.icu:icu4j:jar:4.6 in nexus (http://my_nexus_repository:8081/nexus/content/groups/public) -> [Help 1]
I see that icu4j-4.6.jar does exist in the Maven central repository. On my local nexus repository, it doesn't exist. I see only icu4j-4.6.pom exists on my local nexus repository.
It's not like my nexus repository setting is totally broken. maven project has successfully downloaded numerous jar files from multiple public repositories via my local nexus maven repository except icu4j-4.6.jar.
I don't understand why I'm having a problem with only icu4j-4.6.jar. Would it be incorrectly cached on either my local maven or nexus maven repository?
If it was incorrectly cached, how can I clean the local maven or nexus maven repository?
The similar problem is described at
Missing maven dependency using nexus setup
icu4j-4.6.jar does not show up in the search list. Only icu4j-4.6.pom shows up in the search list. I don't think is Snapshot VS Release issue because icu4j-4.6.jar seems release jar.
Is it possible that the nexus repo just stopped responding for a while? You can try mvn -X (or -d?) to get detailed info about what is going on. You might also try configuring an alternative repo.
Perhaps you haven't enabled remote index downloads from Maven Central. This would explain why only the POM file appears in your local search (The only file which has been downloaded via the proxy repo).
There might be another issue causing the download failure for the jar itself.... I suppose try and solve one problem at a time :-)
Try adding -U to your mvn arguments to force an update of your local repository.
You could also have corrupt meta data in the repo. In which case, delete that artifact from the repo's cache and let it refresh.
If the artifact in question was cached in properly from the proxy repository, using mvn -U will fix the problem
However if you are seeing pom on your nexus ,this usually happens when the artifact from the proxy repository is not cached in properly. The way to fix is
1) Browse to the component in the Proxy Repository.
2) Invalidate the cache for the repository and reindex the Nexus repository.
3) run mvn clean -U