Non-resolvable parent POM for xxx - java

I'm trying to package a maven project and the IDEA console says "Non-resolvable parent POM for xxx".
The parent pom has been put in my maven local repository but can not be resolved by the submodules.
The submodule's pom.xml reports errors like this.
The parent pom.xml looks like this
<groupId>com.github.comctrl</groupId>
<artifactId>ComCtrl-Cloud</artifactId>
<version>1.0.0</version>
<modules>
<module>comctrl-auth</module>
<module>comctrl-common</module>
<module>comctrl-admin</module>
<module>service-org</module>
<module>service-administrative-division</module>
<module>service-standard-address</module>
</modules>
<packaging>pom</packaging>
<name>ComCtrl-Cloud</name>
The project seems like downloading the parent pom from the central repository and is not able to find it. It is supposed to resolve the pom.xml and download dependencies needed by submodules. I'm not sure what's going on. I'll be appreciated if anyone can help me!

I didn't put the package on the right path, the right path should be ../local_repo/com/github/comctrl.

Related

Compilation error with maven

I have a compilation error in one of my projects
Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile
because it does not find all the classes from another project that I already included using
<dependency>
<groupId>com.laberint</groupId>
<artifactId>laberint-core</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>
and I don't have any compilation problems from Eclipse. I already deleted all the repository.
The errors are because a missing classes that all are in the laberint-core artifact. I already deleted the whole repository folder
I also installed the jar
mvn install:install-file -Dfile=laberint-core-0.0.1-SNAPSHOT.jar -DgroupId=com.laberint -DartifactId=laberint-core -Dversion=0.0.1-SNAPSHOT -Dpackaging=jar
Simply create a jar from your another project and add it in local lib directory of your current project. Another option is install the jar file in to your local maven repository like below:-
mvn install:yourlocal-jarfile
-Dfile=<path-to-your jar>
-DgroupId=<group-id> --> the group that the file should be registered under
-DartifactId=<artifact-id> --> give a artifact name to your jar
-Dversion=<version> --> version of your jar file
-Dpackaging=<packaging> --> jar
-DgeneratePom=true
Also you can try with below option:-
<dependency>
<groupId>com.laberint</groupId>
<artifactId>laberint-core</artifactId>
<version>0.0.1-SNAPSHOT</version>
<systemPath>/pathto/yourJar.jar</systemPath>
</dependency>
Hope this will help your. Good Luck!!!
As you stated in your comment you are developing the laberint-core project in the same Eclipse workspace as the project you are trying to build. The problem you have is that while Eclipse knows each project in your workspace and can resolve those project dependencies, Maven does not have this Information which means that it searches the repositories (your local one in ~/.m2 and Maven Central) for the dependency.
As you said, you have already installed the laberint-core project to your local Maven repository via mvn install. That's why Maven can find the dependency at all and you do not get a dependency could not be resolved exception but I would guess that you installed the dependency some time ago and so some of the classes that your created in the Eclipse project after installing are missing.
There are two ways how you can resolve this issue
Create and install the dependency jar each time before you build the main project
This means some more manual overhead when you are building the main project but it can be automated if you are only building in Eclipse and not directly from the command line.
Create an aggregator project as shown here.
This would basically be a third project that consists only of a pom.xml file that looks somewhat like this:
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.laberint</groupId>
<artifactId>aggregator</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>pom</packaging>
<modules>
<module>relative/path/to/laberint-core</module>
<module>relative/path/to/laberint-main</module>
</modules>
</project>
To build the project you would then call the goals you called on the main project before on the aggregator project. Basically if you called mvn package before from the root directory of the main project you would now change to the root directory of the aggregator project and call mvn package. By convention the aggregator pom should lay in the parent directory of its modules.

Maven project that depends on other project

After i've been through some stackoverflow questions and documents about maven pom.xml relations i am still confused.
I have a project with its own pom.xml
-src/MyProject
-src/MyProject/POM.XML
Now i need to include another 3rd Party project
-src/MyProject
-src/MyProject/POM.XML
-src/OtherProject
-src/OtherProject/POM.XML
I need now to tell Maven when its building the MyProject POM.XML the other POM.XML has to be processed and included.
Reason: I need not only the jar built from OtherProject as a dependency, but what is more important: i need all the dependencies (jars) from the OtherProject as well for MyProject (and i dont want to enter every jar as a dependency manually for MyProject which are already correctly defined in the OtherProjects POM.XML).
What are possible solutions to do this?
You can make a multi-module maven application that consist of several projects (called "modules"). The multi-module application nests all the projects and the so-called master pom.xml, in which the application modules are defined. Each module will have to hold its own pom.xml, also.
So, your directory structure would like:
/application
|---/project1
|---/project2
|---pom.xml
The master pom.xml will define the application modules:
<project ...>
<modelVersion>4.0.0</modelVersion>
<packaging>pom</packaging>
<modules>
<module>project1</module>
<module>project2</module>
</modules>
<dependencyManagement> ... </dependencyManagement>
...
</project>
Defined like this, project1 will build before project2.

How to include a maven module outside of the project context?

I'd like to have a module in some kind of global project directory, so that I can include that module in all other projects that use that common code.
But how can I then tell a maven parent pom to include and compile this global shared module?
The following does not work:
svn/MyGlobalProject/project-commons/pom.xml //should be shared among different projects
svn/MyProject/web-parent/trunk/pom.xml //the parent pom used to build the application
svn/MyProject/web-parent/trunk/project-domain/pom.xml //submodule 1
svn/MyProject/web-parent/trunk/project-web/pom.xml //submodule 2
parent pom.xml:
<project>
<groupId>de.project</groupId>
<artifactId>project-parent</artifactId>
<packaging>pom</packaging>
<modules>
<module>project-domain</module>
<module>project-web</module>
<module>../project-commons</module> <!-- Error -->
</modules>
</project>
mvn package results in:
Child module trunk\project-commons of trunk\pom.xml does not exist
If you run mvn install on that global project, it will be installed in your local repository. Your other projects can then reference it as a dependency:
<dependency>
<groupId>whatever</groupId>
<artifactId>project-commons</artifactId>
<version>1.0</version>
</dependency>
The downside of this simplistic approach is that your other projects won't compile until you've checked-out project-commons and run mvn install.
A more advanced approach is to deploy a network-accessible repository (such as Artifactory or Nexus) which you can deploy global artifacts to. Artifactory has a community edition which is free. You can then list this repository in your settings file and Maven will resolve artifacts that are uploaded to it.
Using relative path to include some submodules is not a good practice...you will have a lot of problems.
Can not you just put the common project as a dependency of the parent module...
In this way you will have that "common project" in all the submodule that declare the parent project as a parent...
Why do you want to compile your "common" project every time you compile the parent pom?
Edited:
YOUR SVN:
svn/MyGlobalProject/project-commons/pom.xml //should be shared among different projects
svn/MyProject/web-parent/trunk/pom.xml //the parent pom used to build the application
svn/MyProject/web-parent/trunk/project-domain/pom.xml //submodule 1
svn/MyProject/web-parent/trunk/project-web/pom.xml //submodule 2
PARENT POM.XML:
<project>
<groupId>de.project</groupId>
<artifactId>project-parent</artifactId>
<packaging>pom</packaging>
<dependencies>
<dependency>
<groupId>de.project</groupId>
<artifactId>project-commons</artifactId>
<version>${common.project.version}</version>
<dependency>
<dependencies>
<modules>
<module>project-domain</module>
<module>project-web</module>
</modules>
Just like this...
in that way project-domain and project-web will inherit that dependency, and you will able to use it everywhere you want in submodules...
Than the use of dependency management could be a good improvements

Eclipse NoSuchMethod exception; configuring build path

I have a maven project which actually builds as multiple java projects. Project B contains a class which is a child of a class sin Project A. When I try to run this class in a debugger I get a NoSuchMethod error when the method tries to call any functionality from it's parent.
The Maven setup is designed to compile every single project and place it in the maven repository so other projects can find them (it has a sense of dependency so it builds pre-req projects firsts). This is all good for deployment, but I don't want to force people debugging in eclipse to do a maven install every time the start up their debugger. Instead I tried adding pre-req projects to the class path of the applicable projects (build path -> add class folder). This doesn't work. I think it's due to having both the maven repository and the class path in my build path? but the class folders should be parsed forced and the newer class folders should be parsed before the maven install right?
How can I configure this to work without needing to re-do a maven install each time?
What exactly do your pom files look like? I often use a setup where I have one parent Maven project that is comprised of other Maven sub projects.
I will have a parent pom that looks something like this:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<groupId>put group id here</groupId>
<artifactId>name of artifact id</artifactId>
<version>0.2.0-SNAPSHOT</version>
<packaging>pom</packaging>
<modules>
<module>example-subproject-1</module>
<module>example-subproject-2</module>
</modules>
</project>
I'll then have pom files in the subprojects that look like this (assume this is the pom file for subproject 1):
<?xml version="1.0"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<parent>
<artifactId>artifact id of parent pom</artifactId>
<groupId>group id of parent pom</groupId>
<version>version number of parent pom</version>
</parent>
<groupId>group id</groupId>
<artifactId>artifact id</artifactId>
<packaging>packaging</packaging>
<version>1</version>
<name>put name here</name>
<dependencies>
<dependency>
<groupId>group id of example subproject 2</groupId>
<artifactId>example-subproject-2</artifactId>
<version>version number of example subproject 2</version>
</dependency>
</dependencies>
</project>
When I have things set up this way, I can compile the entire project if I'm in the root directory. If I just want to compile a specific directory, I just change into that directory. Make sure to include any needed subprojects in your dependencies section.
Make sure you have the m2eclipse plugin installed.
http://eclipse.org/m2e/download/
Also, install the m2eclipse-wtp plugin
http://marketplace.eclipse.org/content/maven-integration-eclipse-wtp#.UUdUhBxwrIU
Make sure you have created your projects as 'Maven' projects. So, if you look at your 'ProjectA->Properties->Builders', you should see a 'Maven Project Builder'.
If you follow all above steps, your project dependencies should resolve correctly and you should not have errors.
If you still have errors, pls post your eclipse project structure.

Is is legal to have relativePath to parent pom in a repository?

I found this artifact pom in the maven 2 central repository:
http://search.maven.org/remotecontent?filepath=javax/servlet/jsp/jsp-api/2.1.2/jsp-api-2.1.2.pom
It includes:
...
<parent>
<groupId>org.glassfish.web</groupId>
<artifactId>jsp</artifactId>
<version>2.2</version>
<relativePath>../pom.xml</relativePath>
</parent>
<modelVersion>4.0.0</modelVersion>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<packaging>jar</packaging>
<version>${jsp-api.version}</version>
<name>JavaServer Pages(TM) API v${jsp-api.version}</name>
....
I encountered a problem when I tried to resolve with Ivy the dependency:
<dependency org="javax.servlet.jsp" name="jsp-api" rev="2.1.2" />
Ivy could not resolve the dependency and printed out this error:
[ivy:resolve] nexus: bad revision found in http://XXX/nexus/content/groups/public/javax/servlet/jsp/jsp-api/2.1.2/jsp-api-2.1.2.pom: expected='2.1.2 found='${jsp-api.version}'
Now wonder if it is ok that a pom file in a repository references relatively to a parent pom?
From the POM Reference: "Notice the relativePath element. It is not required, but may be used as a signifier to Maven to first search the path given for this project's parent, before searching the local and then remote repositories."
That effectively means that the relativePath is only used if it's found, and then Maven falls back to normal repository lookup. In this case, repository lookup should work fine, as the referenced artifact is available in central. Are you using a local repo or proxy? It could be that your proxy settings are preventing Ivy from finding the parent pom.
Yes, it is legal.
http://maven.apache.org/guides/introduction/introduction-to-the-pom.html#Project_Inheritance
From the error, it looks like it's not resolving ${jsp-api.version} for you.

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