apache/maven · error · ArtifactMetadataRetrievalException

Failed to process POM for " + artifact.getId() + ": " + miss

Error message

Failed to process POM for " + artifact.getId() + ": " + missingParentPom.getMessage()

What it means

Thrown by MavenMetadataSource when it tries to build the MavenProject of an artifact (to read its transitive dependencies) and project building fails specifically because the POM references a parent that cannot be resolved. hasMissingParentPom() extracts the ModelProblem for the absent parent, and the ArtifactMetadataRetrievalException carries that problem's original exception plus the artifact coordinates.

Source

Thrown at compat/maven-compat/src/main/java/org/apache/maven/project/artifact/MavenMetadataSource.java:556

                    configuration.setRemoteRepositories(repositoryRequest.getRemoteRepositories());
                    configuration.setValidationLevel(ModelBuildingRequest.VALIDATION_LEVEL_MINIMAL);
                    configuration.setProcessPlugins(false);
                    configuration.setRepositoryMerging(ProjectBuildingRequest.RepositoryMerging.REQUEST_DOMINANT);
                    MavenSession session = legacySupport.getSession();
                    if (session != null) {
                        configuration.setSystemProperties(session.getSystemProperties());
                        configuration.setUserProperties(session.getUserProperties());
                    } else {
                        configuration.setSystemProperties(getSystemProperties());
                        configuration.setUserProperties(new Properties());
                    }
                    configuration.setRepositorySession(legacySupport.getRepositorySession());

                    project = projectBuilder.build(pomArtifact, configuration).getProject();
                } catch (ProjectBuildingException e) {
                    ModelProblem missingParentPom = hasMissingParentPom(e);
                    if (missingParentPom != null) {
                        throw new ArtifactMetadataRetrievalException(
                                "Failed to process POM for " + artifact.getId() + ": " + missingParentPom.getMessage(),
                                missingParentPom.getException(),
                                artifact);
                    }

                    String message;

                    if (isMissingPom(e)) {
                        message = "Missing POM for " + artifact.getId();
                    } else if (isNonTransferablePom(e)) {
                        throw new ArtifactMetadataRetrievalException(
                                "Failed to retrieve POM for " + artifact.getId() + ": "
                                        + e.getCause().getMessage(),
                                e.getCause(),
                                artifact);
                    } else {
                        message = "Invalid POM for " + artifact.getId()
                                + ", transitive dependencies (if any) will not be available"

View on GitHub (pinned to e4093d4e12)

Solutions

Verify the parent groupId:artifactId:version exists in a repository you actually use (search Central / your Nexus)
Add the missing repository to settings.xml (or fix the mirror/mirrorOf rules excluding it)
If offline (-o), remove it or pre-seed the local repo with the parent
Delete the child's cached directory in ~/.m2/repository and retry to rule out corrupt metadata
Fix the parent version in the POM if it was typo'd or never released

Example fix

<!-- before -->
<parent>
  <groupId>com.corp</groupId><artifactId>corp-parent</artifactId>
  <version>4.2.1</version> <!-- never published -->
</parent>
<!-- after -->
<parent>
  <groupId>com.corp</groupId><artifactId>corp-parent</artifactId>
  <version>4.2.0</version> <!-- released version available in repos -->
</parent>

Defensive patterns

Strategy: try-catch

Validate before calling

// Before resolving, confirm the parent coordinates exist in your effective repos
// (quick check: artifact exists at <repoUrl>/<groupId as path>/<artifactId>/<version>/)

Try / catch

try {
    ArtifactMetadataSource.retrieve(...);
} catch (ArtifactMetadataRetrievalException e) {
    if (e.getMessage().startsWith("Failed to process POM")) {
        // parent of a transitive dep is unresolvable: exclude or pin
        addExclusion(artifact, failingDependency);
    }
}

Prevention

Publish parent POMs before children (release order matters)
Ensure repositories hosting parents are configured and mirror-exempt
Use dependencyManagement to pin versions whose parents are problematic

When it happens

Trigger: retrieve() is called for artifact X; projectBuilder.build on X's POM fails; the failure contains a missing-parent problem (parent POM not in any repo, wrong parent version, or parent itself unreachable). Common shapes: <parent><version> pointing at a version never published, or a corporate parent not reachable in the current environment.

Common situations: Company parent POMs hosted on a repository not configured in settings.xml; aggregator children checked out without the parent and offline mode on; parent version bump published before children (or never); mirrors blocking the repo that hosts the parent.

Related errors

AI-assisted analysis of apache/maven@e4093d4e12 (2026-08-21). Data as JSON: /api/errors/b94d55d9c43ce5fa. Report an issue: GitHub.