Tomcat - java.io.FileNotFoundException - "WARNING: Failed to scan"
Problem
In the tomcat log, there are multiple java.io.FileNotFoundException exceptions similar to the following:
org.apache.tomcat.util.scan.StandardJarScanner scan
WARNING: Failed to scan [file:/tmp/sealights/httpcore-4.4.5.jar] from classloader hierarchy
java.io.FileNotFoundException: /tmp/sealights/httpcore-4.4.5.jar (No such file or directory)
at java.util.zip.ZipFile.open(Native Method)
at java.util.zip.ZipFile.<init>(ZipFile.java:219)
at java.util.zip.ZipFile.<init>(ZipFile.java:149)
at java.util.jar.JarFile.<init>(JarFile.java:166)
at java.util.jar.JarFile.<init>(JarFile.java:130)
at org.apache.tomcat.util.scan.JarFileUrlJar.<init>(JarFileUrlJar.java:60)
at org.apache.tomcat.util.scan.JarFactory.newInstance(JarFactory.java:43)
at org.apache.tomcat.util.scan.StandardJarScanner.process(StandardJarScanner.java:322)
at org.apache.tomcat.util.scan.StandardJarScanner.scan(StandardJarScanner.java:272)
at org.apache.catalina.startup.ContextConfig.processJarsForWebFragments(ContextConfig.java:1887)
at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1127)
at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:779)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:306)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:95)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5202)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:725)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:701)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:717)
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:940)
at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1816)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)Cause
This is not an error, but rather just a warning that was introduced in Tomcat version 8.0.34 after fixing Apache's Bug 59226
Solution
Since Tomcat 8.0.38 you can configure and disable the scanning of the MANIFEST.MF file, see The Jar Scanner Component
To turn scanning off, add the following line in context.xml:
<Context>
<JarScanner scanManifest="false"/>
</Context>References
https://bz.apache.org/bugzilla/show_bug.cgi?id=59226
https://bz.apache.org/bugzilla/show_bug.cgi?id=59961
https://tomcat.apache.org/tomcat-8.0-doc/config/jar-scanner.html
https://stackoverflow.com/questions/42329948/upgrade-from-tomcat-8-0-39-to-8-0-41-results-in-failed-to-scan-errors