Maven distinct dependencies? - maven

I wonder if it is possible, to stop Maven 3.0 downloading old libraries and use only distinct versions.
(prefering the local repo and the versions where i downloaded Javadoc and sources manually)
For example using JUnit 3.8.2, 4.8.1 and the newest 4.x, but never <3.8.1, 4.5, 4.6-Snapshot etc.
Background: I have my actual projects and local repo on first drive (SSD) with limited space.
If i try an maven archetype to start a new project (often for learning a new theme), maven like downloading i.e. junit 4.5
but i don't like to edit the pom manually looking over my local versions, thinking about compatibilties
and i don't like to purge and download the prefered dependencies again and again.
Are there any tools, plugins, settings or best practices to get this going ?
What i tried so far...
going Offline doesn't help cause my preferred IDE offer download manually only for doc+src
=> "Could not resolve dependencies... The repository system is offline but the artifact ... is not available in the local repository."
best practice for now is (netbeans) in context menu "Remove
dependecy" on project and "Add as Dependecy.." from local repository
tree. (like screenshots ?)

After reading much new stuff i finally agree to Spencer Kormos:
If you're using archetypes, there's not much you can do...
Best practice for me is now this:
Small solution
- create the pom using an archetype
- add <dependencyManagement../> decribing the prefered dependency in the top of the pom
- add <scope>provided</scope>
- optionaly you can add the <exclusions.. />
- remove the conflicting <version../> tags in the generated pom
- the <dependencyManagement../> section i will use for copy/paste in other projects
Greater solution (hopefully) ?
- create a parent/master pom with <dependencyManagement../> of prefered artifacts
- use the from archetype generated pom as module or child-project
- use the master pom for grouping dependencies with <packaging>pom</packaging>
Some of the stuff i read the last day only two links allowed :-(
Maven-Model (look for dependencyManagement under project)
Maven: The Complete Reference, Chapter 3.6.1. Grouping Dependencies

If you specify the versions in your pom.xml (as a dependency, or excluding an older version from a dependency), it shouldn't download any other jars than those specified (or excluded).

Related

Using JGitVer in a tycho pomless build

I would like to use the jgitver maven plugin to automatic define the version of eclipse plugins, features, repository that are built with tycho in pomless mode.
The version management of this 3 plugins are:
jgitver computes a version depending on git tree and tags, create a logical copy of pom, set the new version and associate the new pom to the current plugin in the maven reactor.
For tycho, version are defined in pom and in manifest.mf or feature.xml files. A version consistency check is performed.
When the pom is not defined, pomless maven generates a temporary pom file named .polyglot.build.properties using versions defined in manifest or feature file.
The input path are defined here and depends on PolyglotModelUtil.
The easier way would be a Jgitver evolution to locally update the feature.xml and manifest.MF. It would be a bad idea because a local file would be modified that is not compliant with the plugin philosophy.
A better way would be a Jgitver evolution to generate temporary feature.xml and manifest.MF files that would have been updated with the computed version. Then tycho and tycho-pomless should be forced to use them.
It seems to be possible if i succeed in setting a new ModelProcessor.LOCATION option
Do you think it's an effective way to solve this compatibility problem?
Do you see an alternative?
Thanks for your help.
You could also use directly the jgitver library to participate into your build environment ; it is a pure java library.
The library is the base of both the maven and gradle plugins.

can't find my maven artifacts

I'm working in eclipse and I have a problem that I can't import my personal java libraries.
I created the libraries and 'installed' them into my local maven repo (using mvn install). This created a subdirectory related to the 'version' name that was in the POM file from when I ran the command. Which seemed fine.
So in this directory there where the usual jar files and other stuff.
When I released this file I manually changed the name of the version in the POM. going from 0.0.1-SNAPSHOT to 0.0.1-RELEASE
This seems to have worked as I would have expected.
However I can't seem to find import the new release jar.
Using the maven repositories browser in eclipse I can see that the new artifact is in the 'local' repository.
I try to add the dependency in the following methods:
Select the main project -> Maven -> add dependency.
This adds the dependency details into the pom but with a type value detail of <type>pom.lastUpdated</type>
Select the project pom.xml file -> Maven -> add dependency.
This time the artifact for the 0.0.1-RELEASE is greyed out I can select it, but I guess nothing is actually happening.
The original 0.0.1-SNAPSHOT it selectable, and if I use this I do not have a <type> detail in the pom.
I don't understand why there is a difference in the RELEASE and SNAPSHOT artifacts, as they have both been generated in the same way, and clearly they are both visible in the browser, the contents of the directory on disk are the same. The file names and contents are identical with the exception of the word RELEASE or SNAPSHOT.
I know that I can simply add in the RELEASE jar to my build path, but this seems to be a ridiculous thing to have to do if I intend to use maven (or do I need to do this).
I don't want to use an external repo for storing my artifacts, and I'm not too keen to go to the trouble of installing nexus (or similar) on my local machine (just because I've had trouble with it in the past).
What am I missing so as I can get my maven project to see my local repository and all its artifacts.
Thanks in advance.
David
ps I've already tried things such as mvn dependency:purge-local-repository which definitely pulled in / updated all the local jar dependencies.
So I've managed to work around my problem.
As such this solution is ridiculous, and breaks all the purpose of maven.
So I found (from running maven from the cli) that there was an error in the parent of the project I was attempting to use.
The parent was missing a direct link to the scm plugin (version error).
Once I solved this problem, I then returned to the sub project, and got a lot of errors from missing stuff from the parent.
Essentially it was not 'seeing' all the log4j dependencies.
The solution (well non-solution really).
Add all the log4j dependencies to the sub project.
Edit in SCM and surefire test plugins (as it also started to fail the test code due to missing junit).
So this is great.
I have to define all my dependencies on log4j and in my sub / child project's pom.xml file.
I also need to define them all in my parent's pom.
As it then still refused to run tests in my new project (that used the above as a dependency), and refused to find log4j also. I then decided to add all of these as dependencies for my current project.
Great.
I thought the whole point of maven was I could define my dependency on log4j in my my logging library that I use (which is the dependency), and then it would 'automagically' pull in all the required from this dependency.
Clearly not.
As stated at the start. This is NOT AN ANSWER it is a crazy work around.
My logging library that I use should be able to define its own requirement on a specific log4j version (such as moving from log4j to log4j2), and then when I include this as a maven dependency any change to the required dependency should be seen automatically.
But No : I have to import the dependency on log4j in my other projects also. So now if I had updated my logging library from log4j to log4j2 I would need to go to all my project that use this library and update their pom's to ensure that I have the correct version of log4j.
Seems the whole point of maven has just been lost!
Can someone please tell me where I am going wrong!
David.

Trouble with maven in Netbeans

I want to create maven project in Netbeans. So, I do File->New project->Maven->Java Application. After that I try to build the project and get error:
The POM for org.apache.maven.plugins:maven-surefire-plugin:jar:2.10 is missing, no dependency information available.
But I can build this project from command line with mvn compile. Could uou tell me what is the problem with Netbeans?
NetBeans is using 3.0.4 maven by default. Unless you change that in Tools/Options menu. Are you building with 3.0.4 as well or are you using some earlier versions (2.x)?
That would explain the behaviour because 3.0.4 will not blindly rely on what artifact is in local repository but some additional metadata is also consulted to make sure your project build with the given set of defined repositories.
A common example when the problem occurs to me.
I use central directly everything downloads. when I later add a mirror, all artifacts are checked again through the mirror to make sure they are accessible. if teh Mirror doesn't actually mirror central, I get an error that way.
Another common example is: when building with 2.x, the additional metadata is not written, when later building with 3.0.4, all remote context is checked no matter what is present in local repo and the additional metadata files are constructed.

Using maven and Intellij IDEA, how can I modify a dependency without needing to manually install it every time?

I'm using Intellij-IDEA 11. If there's a solution that works in 12, I'd be willing to upgrade for that.
I built a library that many projects depend on but the library changes often. This library is added to my project's pom.xml as a normal dependency:
<dependency>
<groupId>my.company</groupId>
<artifactId>MyLibrary</artifactId>
</dependency>
This is a typical series of steps I need to take when I add a feature to my project:
Modify some code in my project
Modify some code in the library I depend on
Check to see if the feature works
If not, repeat
Outside of my IDE (which happens to be Intellij-IDEA), this is a straight forward process: I add step 2.5 which is to cd into the dependency's project folder and then mvn install the library.
But I don't know a convenient way to do this in Intellij-IDEA. Ideally, I'd modify the source of the library inside Intellij, click the green play button and the IDE would figure out to use the modified sources of the library.
Right now, since the library is a dependency, it just uses what's already in my local repo. So modifying the source of the library doesn't have an affect until I manually mvn install it.
Note: I've figured out a trick that seems to work. If I modify the project's parent pom to include the library as a maven module and then include the same library as an intellij module, it uses that source instead of the jar in my local repo. But I don't like this solution because I'd never want to commit that modified pom (because the module has to point to a file system path that only exists on my local file system).
I've found a bug in the Intellij-IDEA bug tracker that seems to relate to this: http://youtrack.jetbrains.com/issue/IDEA-25146
I found out a way to do this. First, you add the library's pom.xml in the Maven Projects tool window. Then you Edit your configurations so that they run the install goal of your library. And image of how to do this is provided below.
Click here for a full sized link
Open module setting (F4 on a module), go to Modules, select the dependencies tab in module that depepends on your library.
If the library is a module add a module dependency
If the library isn't a module, I assume it gets built and put somewhere, add that directory to the module dependencies.
The higher up the list the higher its priority
I've similar architecture and here is what I do (and it works very well).
Create an IDEA maven project based on the pom.xml of my main project (the project using the frequently changing library).
Add maven project to my main project (click on the "+" icon in the maven projects tab and choose the pom.xml of my frequently changing library)
EDIT
note: all the modules (from the library and from the main project) have a *-SNAPSHOT version
In more details, the pom.xml of my library project :
<groupId>com.company</groupId>
<artifactId>mylibrary</artifactId>
<version>2.0.1-SNAPSHOT</version>
And the pom.xml of my main project
<groupId>com.company</groupId>
<artifactId>myproject</artifactId>
<version>1.1-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>com.company</groupId>
<artifactId>mylibrary</artifactId>
<version>2.0.1-SNAPSHOT</version>
</dependency>
</dependencies>
I think that IDEA is smart enough to see that the dependency is a SNAPSHOT and that this library is in the current IDEA project (i.e. same IDEA window)... and so IDEA don't look in the local repo since the SNAPSHOT is in the current "workspace".
Hope it clarify the situation.
If I need to run something, I have different options either
defining a new maven run configuration in IDEA to run any maven goal (from any pom.xml in my IDEA project) with any profile.
defining a simple unit test configuration in IDEA (not directly linked with maven except that the classpath is derived from the classpath defined in pom.xml)
defining a new Tomcat/JBoss configuration in IDEA and deploying some artifact in it. (IDEA detect deployable artifacts -like war or ejb- from the pom.xml)
I have the same scenario than you and I am using Intellij 2016.02.
Here is how I solved it:
1 - On Intellij open the maven panel going to View -> Tool Windows -> Maven Projects, then click at the plus green button (add maven project) and select the pom.xml file from the dependency project
2 - On Run/Debug configuration settings, add a before launch task as a maven goal, choosing the Working Directory of the dependency project and in command line just type "install".
3 - Now edit anything in your dependency project, and redeploy your main application, and the changes may affect.
EDITED:
I found a new solution, and it's solved the "update classes and resources" downside, here is what I did:
1 - Do the first step from the previous solution, but remove the install goal from before launch task if you add it on step 2.
2 - Edit the exploded artifact, and add the dependency project "compiled output" element from "Available elements" panel to output left panel.
Changes may work without need to install, and now my "Update classes and resources" works like a charm :)

Maven can't discover workspace projects, junit, other libraries

so I have started using maven (with eclipse, and a local implementation of Sonatype) not that long ago, after getting through the initial pain I though everything was working.... apparently not !
I have my main project POM and all my child POM (I am using a 'flat' hierarchy, so all the sub projects are in the same folder as the parent POM). This seems to be working OK.
The sub project where all started and 'released' and tested before I started using Maven. I went to maven to solve my 'dependencies' problems... or rather make them more complicated in this instance.
Most of the 'Maven' stuff seems to work fine, but I can't resolve the dependencies of my 'sub projects' that have been released into my local ms/repository
Each day I start up eclipse and have the same problems, I have 'unable to resolve imports' on all my personal libraries, and all those that I use for them (such as Log4j, DDlUtils etc).
I thought the whole point of maven was that I would be able to put in an import declaration for a library, add the 'groupID' and other stuff to the child POM (or parent POM). And then have all the jars downloaded automagically when I run
mvn install
against the parent.
However each day I find I have to re-insert the build path to the libraries (internal and external) via the eclipse workspace and point them to the location of the libraries that I have downloaded as maven can't seem to find them anywhere.
Specifically with running Junit test, I can run them from the workspace (using run as junit) and they all pass fine. But if I try to run them with
mvn test
I get an message saying
java.lang;NoClassDefFoundError: org/junit/Assert
(and this is the same from within eclipse running the mvn test or from CLI)
with an error message in the output of
failed to execute goal org.apache.maven.plugins:maven.surfire-plugin:2.10:test
the POM and jar are in my M2_REPO, and I can find it when I search in sonatype, why can't maven find something that is part of its own system, exists in its repo.
but this obviously works just fine when I run via eclipse and point it to an independently downloaded junit library.
I don't know what extra info you may require, and I'm obviously missing something in either the m2e plugin, my maven install or in sonatype.
please help I'm begining to loose my hair!
and may soon be forced to return to an ant/ivy solution (but don't want to have to learn 'yet another tool' (in this case ivy).
Thanks in advance
David.
ps. i'm on a windows XP platform
edit...
can I get maven to build and release the jar and pom even though it thinks it is failing the tests (which is itn't as I'm doing them manually, and they pass just fine).
If I look in the 'effective POM' tab of my parent POM, the plugin stated above is not in there. I guess this means it is a maven config setting, but where do I add it, and why isn't it automatic when I run my first set of maven tests?
edit 2....
I just found this on the apache plugin comments page (http://maven.apache.org/plugins/maven-surefire-plugin/plugin-info.html), so I ran the code on the CLI, mvn surefire:help -Ddetail=true -Dgoal=test lots of stuff was downloaded, and now the tests run, but they fail within maven ? (remember they pass when run from eclipse using 'run as junit test)... so this is nearly a solution...
It sounds like you need make eclipse aware that the projects in question are Maven projects. You may have POMs set up for your projects, but for the m2e plugin to work you need to have either created the project as a Maven project ('New' -> 'Project...' -> 'Maven' -> 'Maven Project...'), or converted it into a Maven project by right clicking it then selecting 'Configure' -> 'Convert to Maven Project'. You will know that a project has been recognised as a Maven project because there will be a little blue 'M' in the top left of its icon, as shown in the screenshot below:
The main thing to note in the above picture is the 'Maven Dependencies' library. This is set up automatically by the m2e plugin. Whenever you add a dependency to a POM then the project's build path will be configured automatically, although sometimes you may need to force it to do so by right clicking the project and selecting 'Maven' -> 'Update Maven Configuration'. The important thing is that if everything is working then you should never have to update the build path yourself. Moveover, if you do update it yourself then any changes you make will likely get overwritten the next time you run the 'Update Maven Configuration' command.
Also worth noting from the picture is that the two dependencies 'mavenProjectTest' and 'primes' have folder icons next to them. This means that they have been picked up as workspace projects. For this to work the project must have 'workspace resolution' enabled, and the projects to be picked up need to be configured as m2e Maven projects as well.
You mention downloading external libraries. You shouldn't need to download any libraries yourself - by adding the right dependency declaration for an external library then Maven will download it from your configured remote repository (the first time anyway - afterwards it will then be able to get it from your local repository). By default, this is the Maven Central repository. To add an external library to your project just follow that link, enter the library in the search box, click on the version link for the version you require, then you will be taken to a page where there will be the dependency XML declaration that you can just copy and paste into your POM.
One more thing that may help is that you should make sure that your source folders follow the Maven default directory structure. That is, your test packages should be contained in a source folder called 'src/test/java', and the main project packages should go in 'src/main/java'. Otherwise Maven will not know where to find your source code. It is possible to configure a POM to tell Maven to expect your source code to be in different source folders, but it is highly recommended that you follow the standard Maven directory structure.
Since you have child modules, my suggestion would be to simplify things by creating a new Maven project from scratch that you can have a play around with. Once you are comfortable with that then try getting m2e to work for your multi-module project.
I remember your pain when first getting to grips with Maven, but it's great once you understand what it's doing and everything is working. I highly recommend reading through the free online book Maven: The Complete Reference - it helped me out a lot when I was getting started with Maven.
I have experienced the same messages and have found a working solution, thanks to one of my organization's Maven experts.
Here was my pom.xml that reproduces your error:
<dependencies>
<dependency>
<groupId>org.junit4</groupId>
<artifactId>org.junit4</artifactId>
<version>4.3.1</version>
</dependency>
</dependencies>
With it, I would get package org.junit does not exist messages and NoClassDefFoundError: org/junit/Assert. Similar to your experience, it worked great from Eclipse, green bars and all.
Here is the pom.xml that works:
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.8.1</version>
<scope>test</scope>
</dependency>
</dependencies>
I copied this from the example at the top of this Using JUnit page.

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