ERROR "version can neither be null, empty nor blank" with unresolved Maven Property in additionalDependencies

[in-fke]

Affected version

3.12.0

Bug description

Getting this ERROR though even "-X" is not telling me which Artifact is making the problem.
To make it more verbose about the artifact that's causing issues, this line
https://github.com/apache/maven-javadoc-plugin/blob/maven-javadoc-plugin-3.12.0/src/main/java/org/apache/maven/plugins/javadoc/AbstractJavadocMojo.java#L2607
should catch any exception and render the artifact in question.

Somewhat related: apache/maven-resolver#1269

[DEBUG] add additional artifact with path C:\dev\M3_REPO\org\apache\logging\log4j\log4j-core\2.25.2\log4j-core-2.25.2.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  28.878 s (Wall Clock)
[INFO] Finished at: 2025-11-16T22:10:23+01:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:3.12.0:javadoc (attach-javadocs) on project NNN: Execution attach-javadocs of goal org.apache.maven.plugins:maven-javadoc-plugin:3.12.0:javadoc failed: version can neither be null, empty nor blank -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:3.12.0:javadoc (attach-javadocs) on project NNN: Execution attach-javadocs of goal org.apache.maven.plugins:maven-javadoc-plugin:3.12.0:javadoc failed: version can neither be null, empty nor blank
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:333)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:316)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:212)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:174)
    at org.apache.maven.lifecycle.internal.MojoExecutor.access$000 (MojoExecutor.java:75)
    at org.apache.maven.lifecycle.internal.MojoExecutor$1.run (MojoExecutor.java:162)
    at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute (DefaultMojosExecutionStrategy.java:39)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:159)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:105)
    at org.apache.maven.lifecycle.internal.builder.multithreaded.MultiThreadedBuilder$1.call (MultiThreadedBuilder.java:193)
    at org.apache.maven.lifecycle.internal.builder.multithreaded.MultiThreadedBuilder$1.call (MultiThreadedBuilder.java:180)
    at java.util.concurrent.FutureTask.run (FutureTask.java:264)
    at java.util.concurrent.Executors$RunnableAdapter.call (Executors.java:539)
    at java.util.concurrent.FutureTask.run (FutureTask.java:264)
    at java.util.concurrent.ThreadPoolExecutor.runWorker (ThreadPoolExecutor.java:1136)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:635)
    at java.lang.Thread.run (Thread.java:840)
Caused by: org.apache.maven.plugin.PluginExecutionException: Execution attach-javadocs of goal org.apache.maven.plugins:maven-javadoc-plugin:3.12.0:javadoc failed: version can neither be null, empty nor blank
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:133)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:328)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:316)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:212)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:174)
    at org.apache.maven.lifecycle.internal.MojoExecutor.access$000 (MojoExecutor.java:75)
    at org.apache.maven.lifecycle.internal.MojoExecutor$1.run (MojoExecutor.java:162)
    at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute (DefaultMojosExecutionStrategy.java:39)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:159)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:105)
    at org.apache.maven.lifecycle.internal.builder.multithreaded.MultiThreadedBuilder$1.call (MultiThreadedBuilder.java:193)
    at org.apache.maven.lifecycle.internal.builder.multithreaded.MultiThreadedBuilder$1.call (MultiThreadedBuilder.java:180)
    at java.util.concurrent.FutureTask.run (FutureTask.java:264)
    at java.util.concurrent.Executors$RunnableAdapter.call (Executors.java:539)
    at java.util.concurrent.FutureTask.run (FutureTask.java:264)
    at java.util.concurrent.ThreadPoolExecutor.runWorker (ThreadPoolExecutor.java:1136)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:635)
    at java.lang.Thread.run (Thread.java:840)
Caused by: java.lang.IllegalArgumentException: version can neither be null, empty nor blank
    at org.apache.commons.lang3.Validate.notBlank (Validate.java:782)
    at org.apache.maven.artifact.ArtifactUtils.notBlank (ArtifactUtils.java:94)
    at org.apache.maven.artifact.ArtifactUtils.key (ArtifactUtils.java:86)
    at org.apache.maven.ReactorReader.findArtifact (ReactorReader.java:96)
    at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolve (DefaultArtifactResolver.java:350)
    at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolveArtifacts (DefaultArtifactResolver.java:261)
    at org.eclipse.aether.internal.impl.DefaultArtifactResolver.resolveArtifact (DefaultArtifactResolver.java:243)
    at org.eclipse.aether.internal.impl.DefaultRepositorySystem.resolveArtifact (DefaultRepositorySystem.java:278)
    at org.apache.maven.plugins.javadoc.AbstractJavadocMojo.resolveDependency (AbstractJavadocMojo.java:2605)
    at org.apache.maven.plugins.javadoc.AbstractJavadocMojo.getPathElements (AbstractJavadocMojo.java:2579)
    at org.apache.maven.plugins.javadoc.AbstractJavadocMojo.addJavadocOptions (AbstractJavadocMojo.java:4554)
    at org.apache.maven.plugins.javadoc.AbstractJavadocMojo.executeReport (AbstractJavadocMojo.java:1998)
    at org.apache.maven.plugins.javadoc.JavadocReport.generate (JavadocReport.java:142)
    at org.apache.maven.plugins.javadoc.JavadocReport.doExecute (JavadocReport.java:307)
    at org.apache.maven.plugins.javadoc.AbstractJavadocMojo.execute (AbstractJavadocMojo.java:1851)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:126)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute2 (MojoExecutor.java:328)
    at org.apache.maven.lifecycle.internal.MojoExecutor.doExecute (MojoExecutor.java:316)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:212)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:174)
    at org.apache.maven.lifecycle.internal.MojoExecutor.access$000 (MojoExecutor.java:75)
    at org.apache.maven.lifecycle.internal.MojoExecutor$1.run (MojoExecutor.java:162)
    at org.apache.maven.plugin.DefaultMojosExecutionStrategy.execute (DefaultMojosExecutionStrategy.java:39)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:159)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:105)
    at org.apache.maven.lifecycle.internal.builder.multithreaded.MultiThreadedBuilder$1.call (MultiThreadedBuilder.java:193)
    at org.apache.maven.lifecycle.internal.builder.multithreaded.MultiThreadedBuilder$1.call (MultiThreadedBuilder.java:180)
    at java.util.concurrent.FutureTask.run (FutureTask.java:264)
    at java.util.concurrent.Executors$RunnableAdapter.call (Executors.java:539)
    at java.util.concurrent.FutureTask.run (FutureTask.java:264)
    at java.util.concurrent.ThreadPoolExecutor.runWorker (ThreadPoolExecutor.java:1136)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run (ThreadPoolExecutor.java:635)
    at java.lang.Thread.run (Thread.java:840)
[ERROR]
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginExecutionException

adding
<verbose>true</verbose>
or
<debug>true</debug>
did not help to pinpoint the problem.

Then, turned out I was using

  <additionalDependency>
    <groupId>jakarta.servlet</groupId>
    <artifactId>jakarta.servlet-api</artifactId>
    <version>${version.servlet}</version>
  </additionalDependency>

and the property version.servlet was not set! So I wonder why this resolved to a blank string!?
Which mechanism resolved to a (presumably) blank string and should not there be a warning about unresolved properties?

[in-fke]

Any thoughts on this? If someone stumbles upon this, it's really hard to analyze.