Maven: Non-resolvable parent POM

问题:

I have my maven project setup as 1 shell projects and 4 children modules. When I try to build the shell. I get:

[INFO] Scanning for projects...
[ERROR] The build could not read 1 project -> [Help 1]
[ERROR]   
[ERROR] The project module1:1.0_A0 (C:\module1\pom.xml) has 1 error
[ERROR] Non-resolvable parent POM: Failure to find shell:pom:1.0_A0 in http://nyhub1.ny.ssmb.com:8081/nexus/content/repositories/JBoss/ was cached in the local repository, resolution will not be reattempted until the update interval of jboss has elapsed or updates are forced and 'parent.relativePath' points at wrong local POM @ line 5, column 11 -> [Help 2]

If I try to build a lone module I get the same error only replace module1, with whatever module it was.

Have them all referencing the parent in their poms.

<parent>
    <artifactId>shell</artifactId>
    <groupId>converter</groupId>
    <version>1.0_A0</version>
</parent>

Here is the relevant parts of the shell pom:

<groupId>converter</groupId>
<artifactId>shell</artifactId>
<version>1.0_A0</version>
<packaging>pom</packaging>
<name>shell</name>


<modules>
    <module>module1</module>
    <module>module2</module>
    <module>module3</module>
    <module>module4</module>
</modules>

回答1:

Just for reference.

The joys of Maven.

Putting the relative path of the modules to ../pom.xml solved it.

The parent element has a relativePath element that you need to point to the directory of the parent. It defaults to ..

回答2:

It can also be fixed by putting the correct settings.xml file into the ~/.m2/ directory.

回答3:

Alternative reason also might be the parent artifact comes from repository which is not accessible from pom.xml, typically private repository. The solution was to provide that repository in pom.xml:

<repositories>
    <repository>
        <id>internal-repo</id>
        <name>internal repository</name>
        <url>https://my/private/repo</url>
        <layout>default</layout>
        <releases>
            <enabled>true</enabled>
        </releases>
        <snapshots>
            <enabled>true</enabled>
        </snapshots>
    </repository>
</repositories>

In my case the problem was even more complicated due to Eclipse: the repository was active only in special profile (<profiles><profile><id>activate-private-repo</id><repositories>...) and Maven GUI in Eclipse didn't allow to set this profile through Ctrl+Alt+P shortcut.

The solution was to temporarily declare repository outside profile (unconditionally), launch Alt+F5 Maven Update Project, activate profile and put repository declaration back into profile. This is rather Eclipse bug, not Maven bug.

回答4:

Just add <relativePath /> so the parent in pom should look like:

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.RELEASE</version>
        <relativePath />
    </parent>

回答5:

Non-resolvable parent POM: This means you cannot resolve the parent repo.

Trun on debug mode:

[DEBUG] Reading global settings from **/usr/local/Cellar/maven/3.5.4/libexec/conf/settings.xml**
[DEBUG] **Reading user settings from /Users/username/.m2/settings.xml**
[DEBUG] Reading global toolchains from /usr/local/Cellar/maven/3.5.4/libexec/conf/toolchains.xml
[DEBUG] Reading user toolchains from /Users/username/.m2/toolchains.xml
[DEBUG] Using local repository at /Users/username/.m2/repository
[DEBUG] Using manager EnhancedLocalRepositoryManager with priority 10.0 for /Users/username/.m2/repository
[INFO] Scanning for projects...
[ERROR] [ERROR] Some problems were encountered while processing the POMs:

Because the parent repo is not part of the maven central. The solution is specify a setting.xml in ~m2/ to help result the parent POM. /Users/username/.m2/settings.xml

In that XML, you might need to specify the repository information.

回答6:

verify if You have correct values in child POMs

GroupId
ArtefactId
Version

In Eclipse, for example, You can search for it:

回答7:

Replace 1.0_A0 with ${project.version}

Run mvn once. This will download all the required repositories. You may switch back to 1.0_A0 after this step.

回答8:

I had similar problem at my work.

Building the parent project without dependency created parent_project.pom file in the .m2 folder.

Then add the child module in the parent POM and run Maven build.

<modules>
    <module>module1</module>
    <module>module2</module>
    <module>module3</module>
    <module>module4</module>
</modules>

回答9:

I had the issue that two reactor build pom.xml files had the same artefactId.

回答10:

I removed

<version>1.0_A0</version>

and it worked (actually my version tag contained ${prject.parent.version}).

Note that my module was not root module.