java - "The POM for ... is missing, no dependency information available" even though it exists in Maven Repository

Question

Problem:

A dependency will not download even though I copied it from the Maven Repository.

When I hover over the dependency in Eclipse, it warns: "Maven Missing artifact org.raml:jaxrs-code-generator:jar:2.0.0".

When I try mvn install or mvn compile it warns: "[WARNING] The POM for org.raml:jaxrs-code-generator:jar:2.0.0 is missing, no dependency information available".

Tried:

• Downloading the jar into the ~/.m2/repository/org/raml/jaxrs-code-generator/2.0.0 folder, then refreshing in the editor.

  • When I install or compile it seems to ignore it.

• Running mvn -U.

  • Same as with install or compile.

In-depth:

    <dependency>
        <groupId>org.raml</groupId>
        <artifactId>jaxrs-code-generator</artifactId>
        <version>2.0.0</version>
    </dependency>

• The dependency exists in the Maven Repository (the version is also correct).

• Using Eclipse EE Neon 4.6.3, Apache Maven 3.3.9, Java 1.8.0_121.

• I have no settings.xml in the ~/.m2 folder.

• I don't use any other repositories, local or otherwise.

Answer 1

Read carefully the warning message :

The POM for org.raml:jaxrs-code-generator:jar:2.0.0 is missing, no dependency information available

The problem is not the jar, but the pom.xml that is missing.
The pom.xml lists the required dependencies for this jar that Maven will pull during the build and overall the packaging of your application. So, you may really need it.

Note that this problem may of course occur for other Maven dependencies and the ideas to solve that is always the same.

The Mule website documents very well that in addition to some information related to.

---

How to solve ?

1) Quick workaround : looking for in the internet the pom.xml of the artifact

Googling the artifact id, the group id and its version gives generally interesting results : maven repository links to download it.
In the case of the org.raml:jaxrs-code-generator:jar:2.0.0 dependency, you can download the pom.xml from the Maven mule repository :

https://repository.mulesoft.org/nexus/content/repositories/releases/org/raml/jaxrs-code-generator/2.0.0/

2) Clean workaround for a single Maven project : adding the repository declaration in your pom.

In your case, add the Maven mule repositories :

<?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">
    <modelVersion>4.0.0</modelVersion>
    ...
    <repositories>
        <repository>
            <id>mulesoft-releases</id>
            <name>MuleSoft Repository</name>
            <url>http://repository.mulesoft.org/releases/</url>
            <layout>default</layout>
        </repository>
        <repository>
            <id>mulesoft-snapshots</id>
            <name>MuleSoft Snapshot Repository</name>
            <url>http://repository.mulesoft.org/snapshots/</url>
            <layout>default</layout>
        </repository>
    </repositories>
    ...
</project>

3) Clean workaround for any Maven projects : add the repository declaration in your settings.xml

 <profile> 
   <repositories>
    ...
    <repository>
      <id>mulesoft-releases</id>
      <name>MuleSoft Repository</name>
      <url>http://repository.mulesoft.org/releases/</url>
      <layout>default</layout>
    </repository>
    <repository>
      <id>mulesoft-snapshots</id>
      <name>MuleSoft Snapshot Repository</name>
      <url>http://repository.mulesoft.org/snapshots/</url>
      <layout>default</layout>
    </repository>
     ...
  </repositories>     
</profile>

Note that in some rare cases, the pom.xml declaring the dependencies is nowhere. So, you have to identify yourself whether the artifact requires dependencies.