[MCHECKSTYLE-287] checkstyle report throws NPE

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.13, 2.14
• Assignee: Michael Osipov
• Reporter: Thomas Scheffler
• Created: 18/Feb/15 07:36
• Updated: 13/Jan/18 10:15
• Resolved: 13/Jan/18 10:15

Description

I don't know what triggers this bug. Somehow org.apache.maven.plugin.checkstyle.AbstractCheckstyleReport.collectArtifacts(String) produces a List which contains the null object. And therefor an exception is thrown here (2.14):

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-site-plugin:3.3:site (default-site) on project oaipmh: Execution default-site of goal org.apache.maven.plugins:maven-site-plugin:3.3:site failed. NullPointerException -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-site-plugin:3.3:site (default-site) on project oaipmh: Execution default-site of goal org.apache.maven.plugins:maven-site-plugin:3.3:site failed.
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:224)
	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:116)
	at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
	at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
	at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:120)
	at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:355)
	at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:155)
	at org.apache.maven.cli.MavenCli.execute(MavenCli.java:584)
	at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:216)
	at org.apache.maven.cli.MavenCli.main(MavenCli.java:160)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
	at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
	at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
	at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.apache.maven.plugin.PluginExecutionException: Execution default-site of goal org.apache.maven.plugins:maven-site-plugin:3.3:site failed.
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:143)
	at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
	... 19 more
Caused by: java.lang.NullPointerException
	at org.apache.maven.plugin.checkstyle.exec.DefaultCheckstyleExecutor.configureResourceLocator(DefaultCheckstyleExecutor.java:852)
	at org.apache.maven.plugin.checkstyle.exec.DefaultCheckstyleExecutor.executeCheckstyle(DefaultCheckstyleExecutor.java:102)
	at org.apache.maven.plugin.checkstyle.AbstractCheckstyleReport.executeReport(AbstractCheckstyleReport.java:474)
	at org.apache.maven.plugin.checkstyle.CheckstyleReport.executeReport(CheckstyleReport.java:156)
	at org.apache.maven.reporting.AbstractMavenReport.generate(AbstractMavenReport.java:255)
	at org.apache.maven.plugins.site.ReportDocumentRenderer.renderDocument(ReportDocumentRenderer.java:219)
	at org.apache.maven.doxia.siterenderer.DefaultSiteRenderer.renderModule(DefaultSiteRenderer.java:319)
	at org.apache.maven.doxia.siterenderer.DefaultSiteRenderer.render(DefaultSiteRenderer.java:135)
	at org.apache.maven.plugins.site.SiteMojo.renderLocale(SiteMojo.java:175)
	at org.apache.maven.plugins.site.SiteMojo.execute(SiteMojo.java:138)
	at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:132)
	... 20 more

Looking at the code, you see a null check is done for the list, bit not for elements of that list:

        // MCHECKSTYLE-225: load licenses from additional artifacts, not from classpath
        if ( additionalArtifacts != null )
        {
            for ( Artifact licenseArtifact : additionalArtifacts )
            {
                try
                {
                    resourceManager.addSearchPath( "jar", "jar:" + licenseArtifact.getFile().toURI().toURL() );
                }
                catch ( MalformedURLException e )
                {
                    // noop
                }
            }
        }

Issue Links

• contains: MCHECKSTYLE-294 NPE on missing license artifact, not fixed previously
• is duplicated by: MCHECKSTYLE-294 NPE on missing license artifact, not fixed previously