I am working on a multi-module maven project and have third party jar which isn't available in central or public repository, I also even don't want to place on public repo. I am providing following plugin directive in my parent pom to install jar in my local maven repository before its dependency is resolved in child project.
Now I provide dependency in child project as;
But I build the project, it successfully adds dependency in local maven repository (places third party jar in .m2 folder) but the at the same time it gives following error. Looks like, it searches this jar file in child projects libs folder as well, while I have already placed it on root (in myproject.parent/libs).
Failed to execute goal org.apache.maven.plugins:maven-install-plugin:3.0.0-M1:install-file (install-
external-non-maven1-jar) on project myProject.core: The specified file 'C:\Users\myuser\git\MyProjectRepository\myproject.parent\myproject.core\libs\be-ixf-java-sdk-jar-with-dependencies.jar' not exists.
I already know scope and systemPath option but I don't want to use it for some reason.
Kindly help in identifying what I am missing ?
The best approach that you could have if your project have a centralized maven repo like nexus setup is to have your third party library also added to the repo. Now , you are having the bin file added to your project and it's not preferable.
If you already have the required jar under your project code in like : libs\*, then why can't you refer the dependency directly in your pom.xml instead of having to install it in your local maven repo and then use it .
<dependency>
<groupId>anything</groupId>
<artifactId>anything</artifactId>
<version>anything</version>
<scope>system</scope>
<systemPath>${basedir}/lib/jar_name.jar</systemPath>
</dependency>
providing the location of the dependency in your project directory should resolve it during build itself.Look at Maven System dependencies.
Since you do not want to change your current setup . Please bear in mind the following about maven pom structure :
Project Aggregation is similar to Project Inheritance. But instead of
specifying the parent POM from the module, it specifies the modules
from the parent POM. By doing so, the parent project now knows its
modules, and if a Maven command is invoked against the parent project,
that Maven command will then be executed to the parent's modules as
well
So the maven-install-plugin execution that you added in main pom.xml might be getting triggered for all your modules because of this reason. You might want to move that to the module that you actually need this lib to be included in.Read maven doc.
Related : force Maven to copy dependencies into target/lib
When you delete a module from a Maven project in IntelliJ, all references to that module turn into compilation errors. Is there a way to exchange references to the module with references to the artefact in the Maven repo, so that everything still compiles?
Now I can get it to work after a restart of IDEA. Don't know why it didn't work at first. I delete a module, and "make project" gives me compile errors, but Maven > Reimport adds dependencies to Maven repo to replace dependencies to the deleted module. Works fine, and I can live with it being a two-step procedure :)
(My dependencies are already in pom.xml, Harmelodic. Modules are created from Maven pom.xml files.)
Let's say I have a maven project which has some maven modules inside.
My main module depends on the other modules, so when I compile the main module they should be compiled together.
The question is, how to add these modules as dependencies to the main module?
I know if I have a custom lib that I want to use with maven, let's say a utilities project, I have to compile the jar of the project, do a mvn install:install-file on it to install it on the local repository and then add it to the pom.xml.
Do I have to do this with all my modules and add the dependency to the pom.xml on my main module? Because if it should be done like this, there will be a lot of work to do when changing code on the other modules.
What is the best practice to use avoid the trouble of compiling/installing the modules to local repository?
The question is, how to add these modules as dependencies to the main module?
The same way you add any other dependency to your maven project. By adding group id, artifact id and version to <dependency> element
Do I have to do this with all my modules and add the dependency to the pom.xml on my main module?
If your main module depends on some module A then only the pom of the main module should contain dependency declaration towards module A. You do that for all the dependencies of your module.
I don't know what you mean by "a lot of work when changing the code on other modules". Maven has nothing to do with code changes, it just builds the projects whatever they look like at the given moment...
What is the best practice to use avoid the trouble of compiling/installing the modules to local repository?
Any project that you invoke mvn install on gets built and it's jar copied to local repository. That's all you need to do to get the jar into the repo. This will also put all the dependent jars, if available, into the local repo.
As for best practices for multi module projects:
If your parent project (the one that has modules inside) has <modules> section that lists the modules of your application, and modules are in subdirectories of your parent project, then you simply mvn install (or whatever you want to do) the parent project and that will cause all the modules to be built in order defined by declared dependencies between them. That means that if your main module has dependency on module A, then module A will be built before the main module. This way you can build and install all your modules with one command. On the other hand this approach makes more tight coupling between modules which is not desired in some cases, so it depends on your use case whether it is a good approach or not.
When I open a POM file and click on the "Dependency Hierarchy" tab at the bottom, it gives me the error, "Project read error". It works with other projects in the same workspace, just not with this one. Any ideas?
EDIT
In response to #Yhn's answer.
Running the compile and package phases outside of Eclipse from the command-line work as expected. It compiles the application and builds the final WAR file.
Eclipse is indeed pointing to the default location of the Maven settings.xml file, so it should be aware of the custom repositories that are defined in it (my company has its own Maven repository).
I can open and edit the POM file from Eclipse, so it must have read/write permissions to the file.
The project is not configured in Eclipse as a Maven project, so I cannot run the package phase from Eclipse (I can only run it from the command-line).
I wonder if it has anything to do with the fact that I was having trouble building the project with Maven 3 because apparently some of the transitive dependencies are configured for Maven 1, which Maven 3 does not support (this is my theory anyway, based on some of the error messages). I can build the project with Maven 2, but I still get messages such as the following:
Downloading: http://dist.codehaus.org/mule/dependencies/maven2/org/codehaus/xfie/bcprov-jdk14/133/bcprov-jdk14-133.pom
[INFO] Unable to find resource 'org.codehaus.xfire:bcprov-jdk14:pom:133' in repsitory mule (http://dist.codehaus.org/mule/dependencies/maven2)
It must be able to find these dependences however, because it downloaded the JARs just fine and can build the application. It seems like the problem is that the dependencies don't have POM files associated with them, which is maybe why they cannot be used with Maven 3. This might also be why I cannot view the Dependency Hierarchy in Eclipse.
EDIT 2
I converted the project to a Maven project by going to "Configure > Convert to Maven Project". When I open the POM file, I see the error:
ArtifactDescriptorException: Failed to read artifact descriptor for woodstox:wst (Click for 140 more)
(woodstox:wst is another transitive dependency of the project). An error appears in the "Markers" view for seemingly every depedency and transitive dependency in my project. However, I can successfully build the project by doing a "Run As > Maven build". (Edit: This might be because this project has no Java source code, but the JARs of the dependencies correctly appear in the final WAR.) The Dependency Hierarchy still gives the same error--"Project read error".
About the "Unable to find resource" messages--but this only appears for a handful of transitive dependencies. The project has many more transitive dependencies, but these messages do not appear for them. It seems like, because the dependencies do not have POM files, that Maven tries to search for them every time the project is built. Is this normal not to have POMs??
How might I go about getting a repo manager? Is this something that would have to be installed on the company's Maven repository or can you install it on your own workstation?
I had this problem with some non-maven jars that I needed to include in my maven project. I put the jars in my local repository using this maven command:
mvn install:install-file -Dfile=/test/gov.nist.xccdf-1.2.jar -DgroupId=gov.nist -DartifactId=xccdf -Dpackaging=jar -Dversion=1.2
Then I referred to them as dependencies in my pom.xml:
<dependency>
<groupId>gov.nist</groupId>
<artifactId>xccdf</artifactId>
<version>1.2</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
This worked fine for a while, but I must have upgraded something in eclipse, and I started getting the error you describe.
The fix is to take them out of the local repository, and redo the install-file asking maven to generate a pom for you:
mvn -DgeneratePom=true install:install-file -Dfile=/test/gov.nist.xccdf-1.2.jar -DgroupId=gov.nist -DartifactId=xccdf -Dpackaging=jar -Dversion=1.2
The command will cause a pom to be generated in the same directory (within your local repo) where the jar is placed.
In recent versions of eclipse maven support, the maven build is still done with maven 2 (if you right-click your pom.xml, choose run as mvn package for example). The dependency analysis is now done with an embedded maven 3 plugin, which doesn't like a dependency that has no pom.xml.
I had the same problem. If you made your project a maven project, you should run:
Right Mouse Click on project | Maven | Update Dependencies or
Right Mouse Click on project | Maven | Update Project Configuration
That worked for me.
Given the information through the comments:
mvn compile/mvn package work through console (I'm assuming outside of eclipse). Based on that, the POM file should be correct and dependencies can be resolved.
However; it could be that eclipse's settings aren't correct. For example, if eclipse has some own maven properties (instead of the default ~/.m2/settings.xml file); I can imagine it to fail resolving dependencies configured in the settings.xml used by maven itself. The settings for this should be in the Eclipse Preferences # Maven > User Settings.
Also make sure that Eclipse can actually read the file (not locked, correct rights, etc).
Should this seem to be correct; can you try to run the mvn goal compile from eclipse? You can do this by right-clicking the project and selecting run as > maven package. That way it should run maven with the same settings as eclipse is using, and might show any additional errors in it's configuration.
--
In response to additional information:
Basically it tells you - when using Maven 2 - that it can't find a dependency resource (in this case bcprov-jdk14) in the given repository (codehaus/mule). When I search that maven module (bcprov-jdk14) I find it in the Maven central repo (through our local nexus) # repo1.maven.org/maven2. Maybe that causes the error you're getting with Maven2?
And as the Maven 3 doc says; for Maven 1.x repo's; you should proxy them through a repo manager that can serve it to you as a maven 2 repository (I believe we do that here too for some repo's through Sonatype Nexus OSS)
ps.: Enabling maven dependency management in eclipse should be enough to be able to use maven run targets; if you would want to test it.
--
Sound like it can be multiple problems... given that the normal maven build works fine, one would think that maven can at least get the artifacts it depends upon and their dependencies... Yet, eclipse doesn't seem to be able to.
Double check if your Eclipse internet connection settings are correct? Since you were talking about a company repo, I'm assuming there will probably also be a proxy (I had to set up my Eclipse to use that one too; though for plugins (see next point)).
Another possibility, from experience, can be a rule-based proxy block on *.pom url requests (our proxy here blocks that to force usage of the local repo manager, how evil and annoying that is :(). You might want to try and open the .pom file it tries to download manually in your browser to see if this is the case (I can't, for example...).
To get the repo set up, you would probably have to ask the one responsible for the repository to add it as a maven2 proxy.
At the very least, it seems Eclipse is having issues getting the dependency poms (which are needed to build the dependency tree) from the internet. You could always try to ask some ICT crew (if they are capable enough...) about it at your company, maybe they have some useful hints.
right click on the project, Maven->Update Project->Tick "Force Update of Snapshots/Releases"
I had the same problem when I added a new dependency to pom.xml without network connection. After this, I had so many problems such as "Missing artifacts", "Missing Descriptor", or "Project Read error". I solved this
delete the bad dependency just added from local repository.
rebuild local index.
re-add the dependency
<properties>
<!-- ********************** -->
<!-- Plugin's properties -->
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.7</java.version>
</properties>
this pom setting worked for me
Usually this happens if there is a typo in the pom that Maven cannot understand and then it throws Project read error. Like in my case I copied a maven dependency snippet and I by passed the version. Instead of typing the actual version # it was getting it dynamically ${asciidoctorj.version} and my pom didn't have this in the properties section. So I got this error. Once I removed that and put a version number it started working.
I had this after copying a local repository folder from another machine. The fix was to go into the repository folder I copied and delete
_remote.repositories along with the 'LastUpdated' files then refresh the Maven dependencies in Eclipse (Alt+F5)
I faced same situation today. In my case it's caused by dependency name in wrong case. E.g.
Project A -> Project B -> Project C
In project B's pm file, I mistakenly specified the dependency artifacts name with "c" in stead of "C".
As in mac os, the files system is case insensitive. so I can build it in command line without detecting this mistake.
In Eclipse it breaks, but it provides very bad error message. In the error list, it says "dependency problem", but the name of dependency is empty. It also can't identify which line in the POM causes the problem.
When try to open "Effective POM" in POM viewer, it will show project read error. In the pop up error dialog box, it will show:
Could not read maven project
java.nio.channels.OverlappingFileLockException
All the messages are useless and misleading.
I finally detected this problem by submit to Jenkins CI after wasted hours of time.
I did maven clean install and the errors were gone
I faced the same issue of "Project read error" while clicking on "Dependency Hierarchy" tab. In my project I had a parent pom and child pom.
Parent pom had a property <appVersion>4.5<appVersion> that was being used in child pom
<version>${appVersion}<version>.
I selected the main project, right click and choose run as maven clean. The console display showed warning that version is using expression but should be a constant. Replacing ${appVersion} with constant value of 4.5 fixed the issue.
I'm in the process of learning maven (and java packaging & distribution) with a new oss project I'm making as practice. Here's my situation, all java of course:
My main project is ProjectA, maven-based in a github repository. I have also created one utility project, maven-based, in github: ProjectB. ProjectA depends on a project I have heavily modified that originally was from a google-code ant-based repository, ProjectC.
So, how do I set up the build for ProjectA such that someone can download ProjectA.jar and use it without needing to install jars for ProjectB and ProjectC, and also how do I set up the build such that someone could check out ProjectA and run only 'mvn package' for a full compile?
(Additionally, what should I do with my modified version of ProjectC? include the class files directly into ProjectA, or fork the project into something that could then be used by as a maven dependency?)
I've been reading around, links such as this SO question and this SO question, but I'm unclear how those relate to my particular circumstance. So, any help would be appreciated. Thanks!
So, how do I set up the build for ProjectA such that someone can download ProjectA.jar and use it without needing to install jars for ProjectB and ProjectC
Assuming ProjectA is a JAR, you can create an executable JAR that bundles the dependencies with the Maven Assembly Plugin (and the predefined jar-with-dependencies descriptor) or with the Maven Shade Plugin.
how do I set up the build such that someone could check out ProjectA and run only 'mvn package' for a full compile?
You have to deploy the dependencies to a repository that can be read over HTTP and to declare this repository in your pom.xml. AFAIK, git-hub doesn't offer any facility for that. But any web hosting service with FTP access (or better, scp) should do the trick. If your project is open source, another option would be to use Sonatype's OSS Repository Hosting service.
Just in case, you might want to read this blog post but you won't learn much more things.
The easiest would still be to organize the 3 projects as a multi-modules maven project and to build all modules.
Additionally, what should I do with my modified version of ProjectC?
From a modularization point of view (assuming you found a solution for the above part about repository), it would certainly make sense to have it as a separate module, especially if there is an opportunity someone can use ProjectC outside your project.
You have to publish the code from the additional dependencies. Two options:
Use the maven-shade-plugin to create a maven artifact containing all the content of the B and C jars, and publish that under your own G/A/V coordinates.
Publish copies of B and C under your own G/A/V coordinates using the maven-deploy-plugin to your forge just as you will publish your own code. Different forges have different policies; but if you abide by the licenses of B and C you should be OK.