JXR Fails with NPE if the .java file is empty (class commented out)

If you build a project and one of your java files exists (but is empty / commented out), JXR generates a NPE

[INFO] Generate "Source Xref" report.
[INFO] Scanning W:\1244 - Knowledge Management System (KMS)\dev\modules\kms-services\src\main\java
Unable to processPath W:\1244 - Knowledge Management System (KMS)\dev\modules\kms-services\src\main\java\com\cswgroup\kms\services\cont
ent\contenthandler\AddCheckOutMetadataHandler.java => W:\1244 - Knowledge Management System (KMS)\dev\modules\kms-services\target/site/
xref\com\cswgroup\kms\services\content\contenthandler\AddCheckOutMetadataHandler.html
[INFO] ------------------------------------------------------------------------
[ERROR] BUILD ERROR
[INFO] ------------------------------------------------------------------------
[INFO] Error during report generation

Embedded error: Error while generating the HTML source code of the projet.
[INFO] ------------------------------------------------------------------------
[INFO] Trace
org.apache.maven.lifecycle.LifecycleExecutionException: Error during report generation
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:559)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeStandaloneGoal(DefaultLifecycleExecutor.java:488)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoal(DefaultLifecycleExecutor.java:458)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoalAndHandleFailures(DefaultLifecycleExecutor.java:306)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeTaskSegments(DefaultLifecycleExecutor.java:273)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.execute(DefaultLifecycleExecutor.java:140)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:322)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:115)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:256)
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:585)
at org.codehaus.classworlds.Launcher.launchEnhanced(Launcher.java:315)
at org.codehaus.classworlds.Launcher.launch(Launcher.java:255)
at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:430)
at org.codehaus.classworlds.Launcher.main(Launcher.java:375)
Caused by: org.apache.maven.plugin.MojoExecutionException: Error during report generation
at org.apache.maven.plugins.site.SiteMojo.execute(SiteMojo.java:389)
at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:412)
at org.apache.maven.lifecycle.DefaultLifecycleExecutor.executeGoals(DefaultLifecycleExecutor.java:534)
... 16 more
Caused by: org.apache.maven.reporting.MavenReportException: Error while generating the HTML source code of the projet.
at org.apache.maven.plugin.jxr.JxrReport.generateXrefForSources(JxrReport.java:202)
at org.apache.maven.plugin.jxr.JxrReport.executeReport(JxrReport.java:165)
at org.apache.maven.reporting.AbstractMavenReport.generate(AbstractMavenReport.java:117)
at org.apache.maven.plugins.site.SiteMojo.generateReportsPages(SiteMojo.java:802)
at org.apache.maven.plugins.site.SiteMojo.execute(SiteMojo.java:301)
... 18 more
Caused by: java.lang.NullPointerException
at org.apache.maven.jxr.CodeTransform.getHeader(CodeTransform.java:651)
at org.apache.maven.jxr.CodeTransform.transform(CodeTransform.java:716)
at org.apache.maven.jxr.CodeTransform.transform(CodeTransform.java:787)
at org.apache.maven.jxr.JXR.transform(JXR.java:195)
at org.apache.maven.jxr.JXR.processPath(JXR.java:114)
at org.apache.maven.jxr.JXR.xref(JXR.java:331)
at org.apache.maven.plugin.jxr.JxrReport.createXref(JxrReport.java:384)
at org.apache.maven.plugin.jxr.JxrReport.generateXrefForSources(JxrReport.java:189)
... 22 more
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1 minute 11 seconds
[INFO] Finished at: Thu Apr 20 16:02:41 BST 2006
[INFO] Final Memory: 22M/67M
[INFO] ------------------------------------------------------------------------