I am getting an error on mvn verify site - maven-plugin

Question

It gives me this error pointing to one of the pom files. I checked the plugin and its not null. I even updated it to the latest version. still doesn't fix it.
Execution default-site of goal org.apache.maven.plugins:maven-site-plugin:3.4:site failed: Anchor name cannot be null

Answer 1

It looks like that exception surfaces in a lot of cases and is incredibly unhelpful.
There was an issue a while back where not having a license name defined in the pom would throw this exception.
I ran into this exception (with version 3.4) where I had a typo in my changes.xml file (verison instead of version). I was only tipped off by seeing that it failed in a ChangesReportGenerator class. Even then I glanced over the typo several times before seeing it.
For anyone else running into this, take the time to check for even the most random typos - it might just be the problem.
For reference, here's the complete error message from the log:
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] example.products.parent ...................... SUCCESS [0.709s]
[INFO] Example Product .............................. FAILURE [2.199s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 13.162s
[INFO] Finished at: Fri Sep 02 12:53:19 CDT 2016
[INFO] Final Memory: 26M/64M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-site-plugin:3.4:site (default-site) on project example.product: Execution default-site of goal org.apache.maven.plugins:maven-site-plugin:3.4:site failed: Anchor name cannot be null! -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-site-plugin:3.4:site (default-site) on project example.product: Execution default-site of goal org.apache.maven.
plugins:maven-site-plugin:3.4:site failed: Anchor name cannot be null!
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:225)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
Caused by: org.apache.maven.plugin.PluginExecutionException: Execution default-site of goal org.apache.maven.plugins:maven-site-plugin:3.4:site failed: Anchor name cannot be null!
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:110)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
... 19 more
Caused by: java.lang.NullPointerException: Anchor name cannot be null!
at org.apache.maven.doxia.sink.XhtmlBaseSink.anchor(XhtmlBaseSink.java:1545)
at org.apache.maven.doxia.siterenderer.sink.SiteRendererSink.anchor(SiteRendererSink.java:253)
at org.apache.maven.doxia.sink.XhtmlBaseSink.anchor(XhtmlBaseSink.java:1533)
at org.apache.maven.plugin.issues.AbstractIssuesReportGenerator.sinkSectionTitle2Anchor(AbstractIssuesReportGenerator.java:181)
at org.apache.maven.plugin.changes.ChangesReportGenerator.constructRelease(ChangesReportGenerator.java:528)
at org.apache.maven.plugin.changes.ChangesReportGenerator.constructReleases(ChangesReportGenerator.java:511)
at org.apache.maven.plugin.changes.ChangesReportGenerator.doGenerateReport(ChangesReportGenerator.java:230)
at org.apache.maven.plugin.changes.ChangesMojo.executeReport(ChangesMojo.java:356)
at org.apache.maven.reporting.AbstractMavenReport.generate(AbstractMavenReport.java:196)
at org.apache.maven.plugins.site.render.ReportDocumentRenderer.renderDocument(ReportDocumentRenderer.java:224)
at org.apache.maven.doxia.siterenderer.DefaultSiteRenderer.renderModule(DefaultSiteRenderer.java:311)
at org.apache.maven.doxia.siterenderer.DefaultSiteRenderer.render(DefaultSiteRenderer.java:129)
at org.apache.maven.plugins.site.render.SiteMojo.renderLocale(SiteMojo.java:182)
at org.apache.maven.plugins.site.render.SiteMojo.execute(SiteMojo.java:141)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
... 20 more
[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
[ERROR]
[ERROR] After correcting the problems, you can resume the build with the command