can't find my maven artifacts - maven

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.

Related

How to debug loading of wrong Maven plugin

In build section of my effective pom there is a Maven plugin that I don't want to use (it was used before, but now I want to remove it).
I removed this plugin from every parent of my project, but is is still applied.
How do I find out where this plugin declaration come from?
UPDATE:
It turns out this plugin was an implicit dependency of another one. It was not declared as such, but referenced from plugin's components.XML leading to runtime dependency injection. The problem was found by pure luck. I think the question is still relevant - it should be possible to find implicit plugin dependencies without wasting a day or two.
Have you run
mvn install
on the parent pom when you deleted the plugin from there?
When you run mvn from submodule it actually looks into your local repository for parent/siblings modules (jars, poms), not to filesystem (compared to maven using the result of the build when you run whole parent project build with submodules).
If it doesn't help, have a look if it's not coming from super pom. You can see super pom on maven website:
http://maven.apache.org/ref/3.0.5/maven-model-builder/super-pom.html

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.

Maven fails to find local artifact

Occasionally maven complains that a particular dependency, which is built and packaged locally, cannot be found in the local repository while building another project that has it as a dependency. We get an error like:
Failed to execute goal on project X: Could not resolve dependencies for project X: Failure to find Y in [archiva repository] was cached in the local repository, resolution will not be reattempted until the update interval of internal has elapsed or updates are forced ->
Where X is the project being built, and Y is the supposedly missing artifact. If you look in the local repository, the artifact is there. This artifact is never installed in our archiva repository, so the problem is purely based in the local repository.
We have tried various profiles in settings.xml, and of course "mvn -U". Neither do any good, nor should they because this artifact never goes any further than the local repository.
The only two things that seem to work are to wait a very long time until maven smartens up, or to completely delete the local repository. Presumably the waiting option is related to the aforementioned update interval.
We have experienced this problem with maven 3.0.2 and 3.0.3. We are using Archiva 1.0.3 (but again this shouldn't be a factor). Any help would be greatly appreciated.
The local Maven repo tracks where artifacts originally came from using a file named "_maven.repositories" in the artifact directory. After removing it, the build worked. This answer fixed the problem for me.
As the options here didn't work for me, I'm sharing how I solved it:
My project has a parent project (with its own pom.xml) that has many children modules, one of which (A) has a dependency to another child (B). When I tried mvn package in A, it didn't work because B could not be resolved.
Executing mvn install in the parent directory did the job. After that, I could do mvn package inside of A and only then it could find B.
Even in offline mode, maven will check remote repositories if there is a _remote.repositories marker for the dependency. If you need to operate in offline mode, you may need to delete these files.
The simple shell command below deletes these marker files. This is safe to do if you only use offline mode for the machine. I would NOT do this on a machine that needs to pull files down from the web.
I have used this strategy on a build server that is disconnected from the web. We have to transfer the repository to it, delete the marker files and then run in offline mode.
On Linux / Unix you can delete the remote repository marker files this way:
cd ~/.m2
find . -name "_remote.repositories" -type f -delete
Maven remembers when it didn't find something. The key is "resolution will not be reattempted until the update interval of internal has elapsed or updates are forced ->"
The quick solution is to delete your local "repository" subdirectory for the problem artifact - assuming you have fixed the problem with it. :)
mvn -U will force update from remote repository - again, assuming you have now populated remote with said artifact.
When this happened to me, it was because I'd blindly copied my settings.xml from a template and it still had the blank <localRepository/> element. This means that there's no local repository used when resolving dependencies (though your installed artifacts do still get put in the default location). When I'd replaced that with <localRepository>${user.home}\.m2\repository</localRepository> it started working.
For *nix, that would be <localRepository>${user.home}/.m2/repository</localRepository>, I suppose.
If you have <repositories/> defined in your pom.xml apparently your local repository is ignored.
Catch all. When solutions mentioned here don't work(happend in my case), simply delete all contents from '.m2' folder/directory, and do mvn clean install.
Even I faced this issue and solved it with 2 ways:
1) In your IDE select project and clean all projects then install all the maven dependencies by right clicking on project -> go to maven and Update project dependencies select all projects at once to install the same. Once this is done run the particular project
2) Else What you can do is check in the pom.xml for the dependencies for which you are getting error and "mvn clean install" those dependent project first and the install maven dependencies of the current project in which you facing issue. By this the dependencies of the local project will be build and jars will be created.
I run to the similar problem when my new project depend on oracle jdbc jar(which I have installed in my local repository and work well for other projects). I tried -U option ,deleting .lastupdate file or the whole directory and downlaod again,but it did not work. finally,I deleted the directory and installed it locally again,it works.
One of the errors I found around Maven is when I put my settings.xml file in the wrong directory. It has to be in .m2 folder under your user home dir. Check to make sure that is in the right place (along with settings-security.xml if you are using that).
I had DependencyResolutionException in Ubuntu Linux when I've installed local artifacts via a shell script. The solution was to delete the local artifacts and install them again "manually" - calling mvn install:install-file via terminal.
This happened because I had http instead of https in this:
<repository>
<id>jcenter</id>
<name>jcenter-bintray</name>
<url>https://jcenter.bintray.com</url>
</repository>
check if if your artifact Y have packaging set to "jar". If you have defined it as "war" by error or copy paste, it will show this strange "was cached in the local repository, resolution will not be reattempted until the update interval of internal has elapsed or updates are forced". I would expect something like "artifact Y is war, jar type expected".
In my case I needed project Y to be a WAR to be deployed through Tomcat, as well as it needed to be a JAR to be able to add it as a dependency in project X.
So in project Y's pom.xml, I added this plugin to create a JAR along with the WAR:
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>3.2.2</version>
<configuration>
<attachClasses>true</attachClasses>
<classesClassifier>classes</classesClassifier>
</configuration>
</plugin>
And while adding the dependency of project Y in project X's pom.xml, I had to add a classifier:
<dependency>
<groupId>groupId.of.project.Y</groupId>
<artifactId>project.Y</artifactId>
<version>1.0-SNAPSHOT</version>
<classifier>classes</classifier>
</dependency>
Note: when you build project Y, you will see 2 packagings in the target folder: project-Y.war and project-Y-classes.jar, so that's why while importing you are specifying the classes classifier to import the JAR and not the WAR.
Here is the long Solution to the problem
(Not Quick fix but will work if no other solution)
You're going to hate me for saying this but this is the truth about open source projects like eclipse. Because Open source is modular and allows you to build and develop a project in many ways with many tools such as maven, spring boot, options for xml or groovy, different eclipse updates & Etc. The problem is that eclipse allows you to run the project with missing maven builds because the IDE is smart enough to resolve dependencies using a remote_repository where it stores and catches the jar files that is not properly built on the project.
Because of this feature, You may actually have local build issues but just like DNS servers; if the solution is not found in the local directory, Eclipse will look for a solution in it's remote cached repository. When you delete the remote_repository and let Maven rebuild it a second time, The project may end up creating more errors and not build a second time or may possibly rebuild a cache that was missing. But that is unlikely.
So the long answer to fix your solution.
This is a project architecture issue!
SOLUTION:
What you need to do is look in to all your dependant project's pom.xml file and the maven dependencies folder in your local project and try to resolve all the missing dependency jars in your maven dependency folder. If you have a referenced library, I suggest moving those jars into your local project's maven dependency folder.
You have to work your way into solving every child project and then navigate into your root project and fix every single project by using Maven -> Build -> clean install (check off "skip tests" & "resolve workspace artifacts") until every project builds with a clean success.
most likely, when you force update your entire solution to all your projects, you will get a list of errors that you have the IDE auto-resolve. The auto-resolve will refer to a easy reference to fix the issue. But to deploy, you have to manually fix the project because Eclipse, Spring & Maven will work well together but there are maybe a few things they don't agree on. So, you have to play diplomat in those situations and figure it out.
That's the sad truth.
All said, I have a list of problems in my project. I have this issue. The war file generated has empty jar folders and the build is not clean without errors unless i force it. The WAR file generate will run a 404 error on tomcat server production and my angular application will throw a Cors-Error when executing the API.
All the errors on my front end project is artificial because the root of all issues is the WAR file generated. It did not generate with dependencies, the Main project did not execute in tomcat and tomcat server cannot run the spring initializer to deploy the cors-policy on the server to allow my angular application to communicate. But all in all, development environment works fine with no issues.
So that is my long ended solution for this thread.
I had the same error from a different cause: I'd created a starter POM containing our "good practice" dependencies, and built & installed it locally to test it. I could "see" it in the repo, but a project that used it got the above error. What I'd done was set the starter POM to pom, so there was no JAR. Maven was quite correct that it wasn't in Nexus -- but I wasn't expecting it to be, so the error was, ummm, unhelpful. Changing the starter POM to normal packaging & reinstalling fixed the issue.
In my case I had to add mavenLocal() in root level gradle dependency
mavenCentral()
mavenLocal()

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.

maven - how does it work? Missing some some jars

I am trying to move my MyEclipes projects to maven. But of course there are problems. After creating a web priject I get missing jar files - about 5
org.springframework.security jar files e.g. org.springframework.security.ldap-3.0.5.RELEASE
show as missing in the jar build path. They are not in the corresponding .m2 directory. I un-installed ME4S, and deleted .m2, which force .me to be rebuilt on re-install, but it has the same problem.
How do I fix this?
It would be very helpful to understand how the .m2 process works - where is this coming from and how is it controlled?
I am not sure about the MyEclipse part, but this seems to be a pure maven question.
Maven (2/3) uses the pom.xml. This file describe your project. In that file you should define a list of dependencies (which can have their own dependencies and so on).
Maven read the pom.xml and build the classpath accordingly using direct and transitive dependencies.
You can use the mvn dependency:tree command to see how your classpath is built.
More on the plugin page

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