This question is a little different than the other "checking for latest dependency version" type questions.
Let's say we have a project, DepProjA, that builds and publishes an artifact for our other Java apps to import as a dependency. For example, AppProj1 lists DepProjA as a dependency in its pom.xml file.
<dependency>
<groupId>com.mycompany.depproj</groupId>
<artifactId>depproja-lib</artifactId>
<version>feature-addthisfeature</version>
</dependency>
As you may notice, DepProjA, publishes "feature" versions of this JAR with the version named after the working branch name. This is so that other teams can test these particular feature updates before they are published as an official version update. If a bug is found and the fix is pushed under the same branch, the "feature" artifact is updated. However,when we rebuild AppProj1 to try and pull and utilize that latest artifact, it seems to be using the previous local version instead.
Is there an option, either in the pom.xml, or the mvn CLI options, so that maven will always pull down the latest artifact instead of using whatever version is cached? I know I can do a "blanket approach" like purging cache and such, but looking for something that targets specific dependencies. Kind of similar with Docker images where the tag itself won't change, but the underlying SHA can be updated when a new version of that tag is published.
An alternate idea I don't even know is possible: When publishing an artifact, is there a way to add custom metadata or labels that I could then reference? For example, I add a "cicdlabel" that could reference the pipeline ID that published the latest version. Then, I could change that in the application's dependency info when I know there is a change:
<dependency>
<groupId>com.mycompany.myproject</groupId>
<artifactId>myproject-lib</artifactId>
<version>feature-addthisfeature</version>
<cicdlabel>12345</cicdlabel>
</dependency>
In Maven by design released artifacts are immutable.
You can not update the same release version of artifact in Maven central.
It ensure that your build is reproducible, when we change content of released artifact the same build can break in the future.
In your case you should use SNAPSHOT versions for your artifact, and SNAPSHOT version can be updated.
You can use updatePolicy for your repository configuration in your settings.xml.
Yo can use mvn -U .. for update SNAPSHOT versions on every build.
I have a Maven project which has several dependencies that:
Are hosted on a third-party artifact repository, which only holds the x most recent artifacts.
Are snapshot versions. (There are no releases available.)
Once I build my project, I need other members of my team to still build that same version of the project several years from now. However:
The dependency snapshot version I used may no longer be available on the third-party repository.
Even if it's available, the dependency may have been updated without changing the snapshot version number.
Is there a way to automatically create a shared repository of the dependency artifacts Maven retrieved when building the project for the first time? This would cause each dependency artifact to only be retrieved once from the third-party repository.
Set up a Nexus or Artifactory server in your company.
Add all the external repositories as remote repositories to that Nexus/Artifactory and run all builds through Nexus/Artifactory.
The Nexus/Artifactory will cache all the artifacts you have used, so no risk that some artifact is not available in the future.
For Snapshot version: If you really need to use Snapshot versions, use versions:lock-snapshots (https://www.mojohaus.org/versions-maven-plugin/lock-snapshots-mojo.html) before, so that you have reproducible version numbers.
I am trying to implement a maven release build on a specific cvs tag. Here is my workflow I'm trying to implement:
Jenkins builds a project every night.
Jenkins deploys the WAR on a internal testserver.
After some time I tag an specific tested nightly build in CVS.
Now I will run a maven release build on that specific tag to make sure that only tested changes are in this release and newer changes are irgnored.
The maven release plugin tags this version and deploys the WAR to an artifactory.
Is it somehow possible to make a maven release on a specific CVS tag/branch? Currently I am able to build specific tags/branches with jenkins and also execute a maven release build on this tag/branch. But when I check the tag of the release version it also contains newer changes which makes it unpossible to create hotfixes for this version or just checkout the correct source for a certain version. Another big problem is that the resulting artifact also contains all changes from the HEAD and not only from the selected tag/branch.
I hope you can help me!
You can specify the name of the tag in the CVS settings
there is anyway to update maven version in cmd?
I have installed maven2.x and i want the newest version, i have been looking for and I've found sth like this:
one:convert convert a Maven 1 project.xml (v3 pom) to a Maven 2 pom.xml (v4 pom).
one:deploy-maven-one-repository deploy an artifact into a Maven 1 remote repository.
one:install-maven-one-repository install an artifact into the Maven 1 local repository.
one:maven-one-plugin package a Maven 1 plugin.
some of this sentence update my maven version?
ty for advance.
Maven has no command to upgrade to Maven 3.X.
You should download and extract new version.
Download the latest Maven version and add the {installation folder}/bin to your Path.
The stuff you've quoted is for converting Maven 1.x projects to 2.x and in project.xml to pom.xml. Maven 1.x project files were written in Jelly, which is a whole different thing. Maven 2.x turned the build logic into fully-Java written plugins.
So, to clear things out -- there are two things:
If you want to upgrade to a newer version of Maven, you need to download it from Maven's site, or use a package manager such as apt, or whatever your distribution uses.
If you would like to migrate your projects from Maven 2.x to 3.x, this should normally work out of the box, unless you have a) your own custom plugins, or b) third-party plugins which depend on Maven 2.x API-s, which contain deprecated stuff. Normally, things will work out of the box for you. For more details on changes, you can always check the release notes.
I am a bit confused about the meaning of a Maven Snapshot and why we build one?
A snapshot version in Maven is one that has not been released.
The idea is that before a 1.0 release (or any other release) is done, there exists a 1.0-SNAPSHOT. That version is what might become 1.0. It's basically "1.0 under development". This might be close to a real 1.0 release, or pretty far (right after the 0.9 release, for example).
The difference between a "real" version and a snapshot version is that snapshots might get updates. That means that downloading 1.0-SNAPSHOT today might give a different file than downloading it yesterday or tomorrow.
Usually, snapshot dependencies should only exist during development and no released version (i.e. no non-snapshot) should have a dependency on a snapshot version.
The three others answers provide you a good vision of what a -SNAPSHOT version is. I just wanted to add some information regarding the behavior of Maven when it finds a SNAPSHOT dependency.
When you build an application, Maven will search for dependencies in the local repository. If a stable version is not found there, it will search the remote repositories (defined in settings.xml or pom.xml) to retrieve this dependency. Then, it will copy it into the local repository, to make it available for the next builds.
For example, a foo-1.0.jar library is considered as a stable version, and if Maven finds it in the local repository, it will use this one for the current build.
Now, if you need a foo-1.0-SNAPSHOT.jar library, Maven will know that this version is not stable and is subject to changes. That's why Maven will try to find a newer version in the remote repositories, even if a version of this library is found on the local repository. However, this check is made only once per day. That means that if you have a foo-1.0-20110506.110000-1.jar (i.e. this library has been generated on 2011/05/06 at 11:00:00) in your local repository, and if you run the Maven build again the same day, Maven will not check the repositories for a newer version.
Maven provides you a way to change this update policy in your repository definition:
<repository>
<id>foo-repository</id>
<url>...</url>
<snapshots>
<enabled>true</enabled>
<updatePolicy>XXX</updatePolicy>
</snapshots>
</repository>
where XXX can be:
always: Maven will check for a newer version on every build;
daily, the default value;
interval:XXX: an interval in minutes (XXX)
never: Maven will never try to retrieve another version. It will do that only if it doesn't exist locally. With the configuration, SNAPSHOT version will be handled as the stable libraries.
(model of the settings.xml can be found here)
The "SNAPSHOT" term means that the build is a snapshot of your code at a given time.
It usually means that this version is still under heavy development.
When the code is ready and it is time to release it, you will want to change the version listed in the POM. Then instead of having a "SNAPSHOT" you would use a label like "1.0".
For some help with versioning, check out the Semantic Versioning specification.
A "release" is the final build for a version which does not change.
A "snapshot" is a build which can be replaced by another build which has the same name. It implies that the build could change at any time and is still under active development.
You have different artifacts for different builds based on the same code. E.g. you might have one with debugging and one without. One for Java 5.0 and one for Java 6. Generally its simpler to have one build which does everything you need. ;)
Maven versions can contain a string literal "SNAPSHOT" to signify that a project is currently under active development.
For example, if your project has a version of “1.0-SNAPSHOT” and you deploy this project’s artifacts to a Maven repository,
Maven would expand this version to “1.0-20080207-230803-1” if you were to
deploy a release at 11:08 PM on February 7th, 2008 UTC. In other words, when you
deploy a snapshot, you are not making a release of a software component; you are
releasing a snapshot of a component at a specific time.
So mainly snapshot versions are used for projects under active development.
If your project depends on a software component that is under active development,
you can depend on a snapshot release, and Maven will periodically attempt
to download the latest snapshot from a repository when you run a build. Similarly, if
the next release of your system is going to have a version “1.8,” your project would
have a “1.8-SNAPSHOT” version until it was formally released.
For example , the following dependency would always download the latest 1.8 development JAR of spring:
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring</artifactId>
<version>1.8-SNAPSHOT”</version>
</dependency>
Maven
An example of maven release process
I'd like to make a point about terminology. The other answers gave good explanations about what a "snapshot" version is in the context of Maven. But does it follow that a non-snapshot version should be termed a "release" version?
There is some tension between the semantic versioning idea of a "release" version, which would seem to be any version that does not have a qualifier such as -SNAPSHOT but also does not have a qualifier such as -beta.4; and Maven's idea idea of a "release" version, which only seems to include the absence of -SNAPSHOT.
In other words, there is a semantic ambiguity of whether "release" means "we can release it to Maven Central" or "the software is in its final release to the public". We could consider -beta.4 to be a "release" version if we release it to the public, but it's not a "final release". Semantic versioning clearly says that something like -beta.4 is a "pre-release" version, so it wouldn't make sense for it to be called a "release" version, even without -SNAPSHOT. In fact by definition even -rc.5 is a release candidate, not an actual release, even though we may allow public access for testing.
So Maven notwithstanding, in my opinion it seems more appropriate only to call a "release" version one that doesn't have any qualifier at all, not even -beta.4. Perhaps a better name for a Maven non-snapshot version would be a "stable" version (inspired by another answer). Thus we would have:
1.2.3-beta.4-SNAPSHOT: A snapshot version of a pre-release version.
1.2.3-SNAPSHOT: A snapshot version of a release version.
1.2.3-beta.4: A stable version of a pre-release version.
1.2.3: A release version (which is a stable, non-snapshot version, obviously).
usually in maven we have two types of builds
1)Snapshot builds
2)Release builds
snapshot builds:SNAPSHOT is the special version that indicate current deployment copy not like a regular version, maven checks the version for every build in the remote repository
so the snapshot builds are nothing but development builds.
Release builds:Release means removing the SNAPSHOT at the version for the build, these are the regular build versions.
A Maven SNAPSHOT is an artifact created by a Maven build and pretends to help developers in the software development cycle.
A SNAPSHOT is an artifact (or project build result ) that is not pretended to be used anywhere, it's only a temporarily .jar, ear, ... created to test the build process or to test new requirements that are not yet ready to go to a production environment.
After you are happy with the SNAPSHOT artifact quality, you can create a RELEASE artifact that can be used by other projects or can be deployed itself.
In your project, you can define a SNAPSHOT using the version element in the pom.xml file of Maven:
<groupId>example.project.maven</groupId>
<artifactId>MavenEclipseExample</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<description>Maven pom example</description>
If you want to understand better Maven you can look into these articles too:
https://connected2know.com/programming/menu-maven-articles/
This is how a snapshot looks like for a repository and in this case is not enabled, which means that the repository referred in here is stable and there's no need for updates.
<project>
...
<repositories>
<repository>
<id>lds-main</id>
<name>LDS Main Repo</name>
<url>http://code.lds.org/nexus/content/groups/main-repo</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
</project>
Another case would be for:
<snapshots>
<enabled>true</enabled>
</snapshots>
which means that Maven will look for updates for this repository. You can also specify an interval for the updates with tag.
simply snapshot means it is the version which is not stable one.
when version includes snapshot like 1.0.0 -SNAPSHOT means it is not stable version and look for remote repository to resolve dependencies
Snapshot simply means depending on your configuration Maven will check latest changes on a special dependency. Snapshot is unstable because it is under development but if on a special project needs to has a latest changes you must configure your dependency version to snapshot version. This scenario occurs in big organizations with multiple products that these products related to each other very closely.
understanding the context of SDLC will help understand the difference between snapshot and the release. During the dev process developers all contribute their features to a baseline branch. At some point the lead thinks enough features have accumulated then he will cut a release branch from the baseline branch. Any builds prior to this time point are snapshots. Builds post to this point are releases. Be noted, release builds could change too before going to production if any defect spot during the release testing.
As the name suggests, snapshot refers to a state of project and its dependencies at that moment of time. Whenever maven finds a newer SNAPSHOT of the project, it downloads and replaces the older .jar file of the project in the local repository.
Snapshot versions are used for projects under active development. If your project depends on a software component that is under active development, you can depend on a snapshot release, and Maven will periodically attempt to download the latest snapshot from a repository when you run a build.
In development phase Maven snapshots everyday looks for newer higher version if available in nexus repository n download it locally for next build.
Four option you can set in respository defination
Always,
Daily (default),
Interval,
Never,
Note: In production release we should not have dependency on snapshot version.
The SNAPSHOT value refers to the 'latest' code along a development branch and provides no guarantee the code is stable or unchanging. Conversely, the code in a 'release' version (any version value without the suffix SNAPSHOT) is unchanging.
In other words, a SNAPSHOT version is the 'development' version before the final 'release' version. The SNAPSHOT is "older" than its release.
During the release process, a version of x.y-SNAPSHOT changes to x.y. The release process also increments the development version to x.(y+1)-SNAPSHOT. For example, version 1.0-SNAPSHOT is released as version 1.0, and the new development version is version 1.1-SNAPSHOT.