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.

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();
    }

View on GitHub (pinned to e4093d4e12)

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

• Unbounded range: {}
• Ranges overlap: {}
• Only fully-qualified sets allowed in multiple set scenario:
• Single version must be surrounded by []: {}
• The artifact has no valid ranges

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