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How do I tell Maven to use the latest version of a dependency?

Posted by: admin November 2, 2017 Leave a comment

Questions:

In Maven, dependencies are usually set up like this:

<dependency>
  <groupId>wonderful-inc</groupId>
  <artifactId>dream-library</artifactId>
  <version>1.2.3</version>
</dependency>

Now, if you are working with libraries that have frequent releases, constantly updating the <version> tag can be somewhat annoying. Is there any way to tell Maven to always use the latest available version (from the repository)?

Answers:

NOTE: This answer applies to Maven 2 only! The mentioned LATEST and RELEASE metaversions have been dropped in Maven 3 “for the sake of reproducible builds”, over 6 years ago.

If you always want to use the newest version, Maven has two keywords you can use as an alternative to version ranges. You should use these options with care as you are no longer in control of the plugins/dependencies you are using.

When you depend on a plugin or a dependency, you can use the a version value of LATEST or RELEASE. LATEST refers to the latest released or snapshot version of a particular artifact, the most recently deployed artifact in a particular repository. RELEASE refers to the last non-snapshot release in the repository. In general, it is not a best practice to design software which depends on a non-specific version of an artifact. If you are developing software, you might want to use RELEASE or LATEST as a convenience so that you don’t have to update version numbers when a new release of a third-party library is released. When you release software, you should always make sure that your project depends on specific versions to reduce the chances of your build or your project being affected by a software release not under your control. Use LATEST and RELEASE with caution, if at all.

See the POM Syntax section of the Maven book for more details. Or see this doc on Dependency Version Ranges, where:

  • A square bracket ( [ & ] ) means “closed” (inclusive).
  • A parenthesis ( ( & ) ) means “open” (exclusive).

Here’s an example illustrating the various options. In the Maven repository, com.foo:my-foo has the following metadata:

<?xml version="1.0" encoding="UTF-8"?><metadata>
  <groupId>com.foo</groupId>
  <artifactId>my-foo</artifactId>
  <version>2.0.0</version>
  <versioning>
    <release>1.1.1</release>
    <versions>
      <version>1.0</version>
      <version>1.0.1</version>
      <version>1.1</version>
      <version>1.1.1</version>
      <version>2.0.0</version>
    </versions>
    <lastUpdated>20090722140000</lastUpdated>
  </versioning>
</metadata>

If a dependency on that artifact is required, you have the following options (other version ranges can be specified of course, just showing the relevant ones here):

Declare an exact version (will always resolve to 1.0.1):

<version>[1.0.1]</version>

Declare an explicit version (will always resolve to 1.0.1 unless a collision occurs, when Maven will select a matching version):

<version>1.0.1</version>

Declare a version range for all 1.x (will currently resolve to 1.1.1):

<version>[1.0.0,2.0.0)</version>

Declare an open-ended version range (will resolve to 2.0.0):

<version>[1.0.0,)</version>

Declare the version as LATEST (will resolve to 2.0.0) (removed from maven 3.x)

<version>LATEST</version>

Declare the version as RELEASE (will resolve to 1.1.1) (removed from maven 3.x):

<version>RELEASE</version>

Note that by default your own deployments will update the “latest” entry in the Maven metadata, but to update the “release” entry, you need to activate the “release-profile” from the Maven super POM. You can do this with either “-Prelease-profile” or “-DperformRelease=true”


It’s worth emphasising that any approach that allows Maven to pick the dependency versions (LATEST, RELEASE, and version ranges) can leave you open to build time issues, as later versions can have different behaviour (for example the dependency plugin has previously switched a default value from true to false, with confusing results).

It is therefore generally a good idea to define exact versions in releases. As Tim’s answer points out, the maven-versions-plugin is a handy tool for updating dependency versions, particularly the versions:use-latest-versions and versions:use-latest-releases goals.

Questions:
Answers:

Now I know this topic is old, but reading the question and the OP supplied answer it seems the Maven Versions Plugin might have actually been a better answer to his question:

In particular the following goals could be of use:

  • versions:use-latest-versions searches the pom for all versions
    which have been a newer version and
    replaces them with the latest
    version.
  • versions:use-latest-releases searches the pom for all non-SNAPSHOT
    versions which have been a newer
    release and replaces them with the
    latest release version.
  • versions:update-properties updates properties defined in a
    project so that they correspond to
    the latest available version of
    specific dependencies. This can be
    useful if a suite of dependencies
    must all be locked to one version.

The following other goals are also provided:

  • versions:display-dependency-updates scans a project’s dependencies and
    produces a report of those
    dependencies which have newer
    versions available.
  • versions:display-plugin-updates scans a project’s plugins and
    produces a report of those plugins
    which have newer versions available.
  • versions:update-parent updates the parent section of a project so
    that it references the newest
    available version. For example, if
    you use a corporate root POM, this
    goal can be helpful if you need to
    ensure you are using the latest
    version of the corporate root POM.
  • versions:update-child-modules updates the parent section of the
    child modules of a project so the
    version matches the version of the
    current project. For example, if you
    have an aggregator pom that is also
    the parent for the projects that it
    aggregates and the children and
    parent versions get out of sync, this
    mojo can help fix the versions of the
    child modules. (Note you may need to
    invoke Maven with the -N option in
    order to run this goal if your
    project is broken so badly that it
    cannot build because of the version
    mis-match).
  • versions:lock-snapshots searches the pom for all -SNAPSHOT
    versions and replaces them with the
    current timestamp version of that
    -SNAPSHOT, e.g. -20090327.172306-4
  • versions:unlock-snapshots searches the pom for all timestamp
    locked snapshot versions and replaces
    them with -SNAPSHOT.
  • versions:resolve-ranges finds dependencies using version ranges and
    resolves the range to the specific
    version being used.
  • versions:use-releases searches the pom for all -SNAPSHOT versions
    which have been released and replaces
    them with the corresponding release
    version.
  • versions:use-next-releases searches the pom for all non-SNAPSHOT
    versions which have been a newer
    release and replaces them with the
    next release version.
  • versions:use-next-versions searches the pom for all versions
    which have been a newer version and
    replaces them with the next version.
  • versions:commit removes the pom.xml.versionsBackup files. Forms
    one half of the built-in “Poor Man’s
    SCM”.
  • versions:revert restores the pom.xml files from the
    pom.xml.versionsBackup files. Forms
    one half of the built-in “Poor Man’s
    SCM”.

Just thought I’d include it for any future reference.

Questions:
Answers:

Please take a look at this page (section “Dependency Version Ranges”). What you might want to do is something like

<version>[1.2.3,)</version>

These version ranges are implemented in Maven2.

Questions:
Answers:

Unlike others I think there are many reasons why you might always want the latest version. Particularly if you are doing continuous deployment (we sometimes have like 5 releases in a day) and don’t want to do a multi-module project.

What I do is make Hudson/Jenkins do the following for every build:

mvn clean versions:use-latest-versions scm:checkin deploy -Dmessage="update versions" -DperformRelease=true

That is I use the versions plugin and scm plugin to update the dependencies and then check it in to source control. Yes I let my CI do SCM checkins (which you have to do anyway for the maven release plugin).

You’ll want to setup the versions plugin to only update what you want:

        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>versions-maven-plugin</artifactId>
            <version>1.2</version>
            <configuration>
                <includesList>com.snaphop</includesList>
                <generateBackupPoms>false</generateBackupPoms>
                <allowSnapshots>true</allowSnapshots>
            </configuration>
        </plugin>

I use the release plugin to do the release which takes care of -SNAPSHOT and validates that there is a release version of -SNAPSHOT (which is important).

If you do what I do you will get the latest version for all snapshot builds and the latest release version for release builds. Your builds will also be reproducible.

Update

I noticed some comments asking some specifics of this workflow. I will say we don’t use this method anymore and the big reason why is the maven versions plugin is buggy and in general is inherently flawed.

It is flawed because to run the versions plugin to adjust versions all the existing versions need to exist for the pom to run correctly. That is the versions plugin cannot update to the latest version of anything if it can’t find the version referenced in the pom. This is actually rather annoying as we often cleanup old versions for disk space reasons.

Really you need a separate tool from maven to adjust the versions (so you don’t depend on the pom file to run correctly). I have written such a tool in the the lowly language that is Bash. The script will update the versions like the version plugin and check the pom back into source control. It also runs like 100x faster than the mvn versions plugin. Unfortunately it isn’t written in a manner for public usage but if people are interested I could make it so and put it in a gist or github.

Going back to workflow as some comments asked about that this is what we do:

  1. We have 20 or so projects in their own repositories with their own jenkins jobs
  2. When we release the maven release plugin is used. The workflow of that is covered in the plugin’s documentation. The maven release plugin sort of sucks (and I’m being kind) but it does work. One day we plan on replacing this method with something more optimal.
  3. When one of the projects gets released jenkins then runs a special job we will call the update all versions job (how jenkins knows its a release is a complicated manner in part because the maven jenkins release plugin is pretty crappy as well).
  4. The update all versions job knows about all the 20 projects. It is actually an aggregator pom to be specific with all the projects in the modules section in dependency order. Jenkins runs our magic groovy/bash foo that will pull all the projects update the versions to the latest and then checkin the poms (again done in dependency order based on the modules section).
  5. For each project if the pom has changed (because of a version change in some dependency) it is checked in and then we immediately ping jenkins to run the corresponding job for that project (this is to preserve build dependency order otherwise you are at the mercy of the SCM Poll scheduler).

At this point I’m of the opinion it is a good thing to have the release and auto version a separate tool from your general build anyway.

Now you might think maven sort of sucks because of the problems listed above but this actually would be fairly difficult with a build tool that does not have a declarative easy to parse extendable syntax (aka XML).

In fact we add custom XML attributes through namespaces to help hint bash/groovy scripts (e.g. don’t update this version).

Questions:
Answers:

The dependencies syntax is located at the Dependency Version Requirement Specification documentation. Here it is is for completeness:

Dependencies’ version element define version requirements, used to compute effective dependency version. Version requirements have the following syntax:

  • 1.0: “Soft” requirement on 1.0 (just a recommendation, if it matches all other ranges for the dependency)
  • [1.0]: “Hard” requirement on 1.0
  • (,1.0]: x <= 1.0
  • [1.2,1.3]: 1.2 <= x <= 1.3
  • [1.0,2.0): 1.0 <= x < 2.0
  • [1.5,): x >= 1.5
  • (,1.0],[1.2,): x <= 1.0 or x >= 1.2; multiple sets are comma-separated
  • (,1.1),(1.1,): this excludes 1.1 (for example if it is known not to
    work in combination with this library)

In your case, you could do something like <version>[1.2.3,)</version>

Questions:
Answers:

Are you possibly depending on development versions that obviously change a lot during development?

Instead of incrementing the version of development releases, you could just use a snapshot version that you overwrite when necessary, which means you wouldn’t have to change the version tag on every minor change. Something like 1.0-SNAPSHOT…

But maybe you are trying to achieve something else 😉

Questions:
Answers:

Who ever is using LATEST, please make sure you have -U otherwise the latest snapshot won’t be pulled.

mvn -U dependency:copy -Dartifact=com.foo:my-foo:LATEST
// pull the latest snapshot for my-foo from all repositories

Questions:
Answers:

By the time this question was posed there were some kinks with version ranges in maven, but these have been resolved in newer versions of maven.
This article captures very well how version ranges work and best practices to better understand how maven understands versions: https://docs.oracle.com/middleware/1212/core/MAVEN/maven_version.htm#MAVEN8855

Questions:
Answers:

The truth is even in 3.x it still works, surprisingly the projects builds and deploys. But the LATEST/RELEASE keyword causing problems in m2e and eclipse all over the place, ALSO projects depends on the dependency which deployed through the LATEST/RELEASE fail to recognize the version.

It will also causing problem if you are try to define the version as property, and reference it else where.

So the conclusion is use the versions-maven-plugin if you can.

Questions:
Answers:

Sometimes you don’t want to use version ranges, because it seems that they are “slow” to resolve your dependencies, especially when there is continuous delivery in place and there are tons of versions – mainly during heavy development.

One workaround would be to use the versions-maven-plugin. For example, you can declare a property:

<properties>
    <myname.version>1.1.1</myname.version>
</properties>

and add the versions-maven-plugin to your pom file:

<build>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>versions-maven-plugin</artifactId>
            <version>2.3</version>
            <configuration>
                <properties>
                    <property>
                        <name>myname.version</name>
                        <dependencies>
                            <dependency>
                                <groupId>group-id</groupId>
                                <artifactId>artifact-id</artifactId>
                                <version>latest</version>
                            </dependency>
                        </dependencies>
                    </property>
                </properties>
            </configuration>
        </plugin>
    </plugins>
</build>

Then, in order to update the dependency, you have to execute the goals:

mvn versions:update-properties validate

If there is a version newer than 1.1.1, it will tell you:

[INFO] Updated ${myname.version} from 1.1.1 to 1.3.2