apache/maven · warning · InvalidArtifactRTException

The version cannot be empty.

Error message

The version cannot be empty.

What it means

--fail-on-severity needs Maven's own SLF4J provider, whose ILoggerFactory also implements org.apache.maven.logging.api.LogLevelRecorder, so Maven can record the maximum level actually logged. If LoggerFactory.getILoggerFactory() returns a different provider (logback, log4j-slf4j2, plain slf4j-simple won the binding race, typical when embedding maven-embedder in an app or via jars on maven.ext.class.path), the recorder cannot be installed, the flag is inert, and this warning explains why.

Solutions

1. Remove the competing SLF4J binding from the classpath or ext classpath so maven-slf4j-provider is selected
2. Run with -X and look for multiple-SLF4J-provider messages; prune the duplicates
3. In embedded setups, enforce the severity policy in the host logging backend configuration instead of --fail-on-severity
4. Keep logging implementation jars off maven.ext.class.path entirely

Example fix

<!-- before: transitively pulled logback outranks maven-slf4j-provider -->
<dependency>
  <groupId>com.example</groupId>
  <artifactId>app-core</artifactId>
</dependency>
<!-- after: exclude the competing binding -->
<dependency>
  <groupId>com.example</groupId>
  <artifactId>app-core</artifactId>
  <exclusions>
    <exclusion>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-classic</artifactId>
    </exclusion>
  </exclusions>
</dependency>

import org.slf4j.LoggerFactory;
import org.apache.maven.logging.api.LogLevelRecorder;

static boolean failOnSeveritySupported() {
    return LoggerFactory.getILoggerFactory() instanceof LogLevelRecorder;
}

When it happens

Trigger: Classpath resolution put a foreign SLF4J factory in charge: an application embedding MavenCli that already binds logback or log4j, or an ext-classpath jar shipping a competing SLF4J provider.

Common situations: Embedding Maven in servers or test harnesses; adding rich logging to Maven via ext classpath extensions; duplicate SLF4J providers from shaded plugin dependencies.

Related errors

• A required class was missing during configuration of mojo
• A required class was missing while executing
• An API incompatibility was encountered while executing
• Could not locate…
• {}

AI-assisted analysis of apache/maven@e4093d4e12 (2026-08-21). Data as JSON: /api/errors/af16b724e1d2f9ce. Report an issue: GitHub.

Appendix: source

Thrown at compat/maven-artifact/src/main/java/org/apache/maven/artifact/DefaultArtifact.java:181

    }

    private void validateIdentity() {
        if (empty(groupId)) {
            throw new InvalidArtifactRTException(
                    groupId, artifactId, getVersion(), type, "The groupId cannot be empty.");
        }

        if (empty(artifactId)) {
            throw new InvalidArtifactRTException(
                    groupId, artifactId, getVersion(), type, "The artifactId cannot be empty.");
        }

        if (empty(type)) {
            throw new InvalidArtifactRTException(groupId, artifactId, getVersion(), type, "The type cannot be empty.");
        }

        if ((empty(version)) && (versionRange == null)) {
            throw new InvalidArtifactRTException(
                    groupId, artifactId, getVersion(), type, "The version cannot be empty.");
        }
    }

    public static boolean empty(String value) {
        return value == null || value.isBlank();
    }

    @Override
    public String getClassifier() {
        return classifier;
    }

    @Override
    public boolean hasClassifier() {
        return classifier != null && !classifier.isEmpty();
    }

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