Maven: Non-resolvable parent POM

114
votes

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>
15
mavenmodulebuild-automationparent-child
if anyone is interested, adding <relativePath>..</relativePath> under <parent></parent> worked for me. – kaptan
run this mvn install -N & mvn install – Se Song
Relative path is for non-conforming projects not a "solution" when the expectation is a pom in the parent folder of the module should be accessible. – Rick O'Shea
In my case it was because of the mistyping in pom.xml file. – Oleksii Kyslytsyn
All possible issues summarized : stackoverflow.com/a/62704660/6172857 – Sumit Badsara

15 Answers

102
votes

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 ..

47
votes

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

22
votes

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.

5
votes

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.

4
votes

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>
2
votes

verify if You have correct values in child POMs 

GroupId
ArtefactId
Version

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

2
votes

<relativePath>

If you build under a child project, then <relativePath> can help you resolve the parent pom.

install parent pom

But if you build the child project out of its folder, <relativePath> doesn't work. You can install the parent pom into your local repository first, then build the child project.

1
votes

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.

1
votes

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>
1
votes

It was fixed when I removed settings.xml from .m2 folder.

0
votes

Add a Dependency in

pom.xml:

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.8.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>
<dependency>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-resources-plugin</artifactId>
        <version>2.4.3</version>
</dependency>
0
votes

I solved that problem on me after a very long try, I created another file named "parent_pom.xml" in child module file directory at local and pasted contents of parent_pom.xml,which is located at remote, to newly created "parent_pom.xml". It worked for me and error message has gone.

0
votes

Inside relative path tag do as follows

<relative>{project_name}/pom.xml</relative>

and then RunAs-> Maven build

It worked for me.

0
votes

I had the following config in the parent pom:

  <properties>
    <revision>1.0-SNAPSHOT</revision>
  </properties>

  <groupId>com.company.org</groupId>
  <artifactId>api-reactor-pom</artifactId>
  <version>$revision</version>
  <packaging>pom</packaging>

And I was getting 'Non-resolvable parent POM' error. I changed version to <version>1.0-SNAPSHOT</version>, and it's gone.

Apache Maven 3.6.3.

-2
votes

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