AFTER upgrade from Spring boot 1.2 to 1.5.2, FileNotFoundException during Tomcat 8.5 Startup

Question

I upgraded Spring Boot from 1.2.0 to 1.5.2.

After that upgrade, Tomcat 8.5 is throwing FileNotFoundException during startup.

Below is one of those exceptions, It is throwing more than ~10 similar exceptions.

I have no idea about the purpose of these jars, In other words, I didn't add <dependency> for these jars in pom.xml.

INFO: Starting Servlet Engine: Apache Tomcat/8.5.11 Apr 06, 2017 3:53:57 PM org.apache.tomcat.util.scan.StandardJarScanner scan WARNING: Failed to scan [file:/C:/Users/myname/.m2/repository/com/sun/xml/ws/jaxws-rt/2.1.7/jaxws-api.jar] from classloader hierarchy java.io.FileNotFoundException: C:\Users\myname\.m2\repository\com\sun\xml\ws\jaxws-rt\2.1.7\jaxws-api.jar (The system cannot find the file specified)     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:48)     at org.apache.tomcat.util.scan.StandardJarScanner.process(StandardJarScanner.java:338)     at org.apache.tomcat.util.scan.StandardJarScanner.scan(StandardJarScanner.java:288)     at org.apache.jasper.servlet.TldScanner.scanJars(TldScanner.java:262)     at org.apache.jasper.servlet.TldScanner.scan(TldScanner.java:104)     at org.apache.jasper.servlet.JasperInitializer.onStartup(JasperInitializer.java:101)     at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5178)     at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)     at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1419)     at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1409)     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) 

Any help would be appreciated.

Answer 1

RootCause:

As per Tomcat Wiki, Servlet 3.0 specification requires Jar scanning during server startup.

Tomcat is using org.apache.tomcat.util.scan.StandardJarScanner for this purpose.

From the javadoc of StandardJarScanner.

The default JarScanner implementation scans the WEB-INF/lib directory followed by the provided classloader and then works up the classloader hierarchy. This implementation is sufficient to meet the requirements of the Servlet 3.0 specification as well as to provide a number of Tomcat specific extensions. The extensions are:

• Scanning the classloader hierarchy (enabled by default) Testing all files to see if they are JARs (disabled by default)

• Testing all directories to see if they are exploded JARs (disabled by default)

• All of the extensions may be controlled via configuration.

Solution1: Spring Boot specific.

We can disable this jar scanning.

I disabled it by adding below property in application-xxx.properties file. This property is Spring Boot specific.

# Comma-separated list of additional patterns that match jars to ignore for TLD scanning.     server.tomcat.additional-tld-skip-patterns=*.jar 

You can find similar properties from Tomcat here.

These properties can be used to configure traditional tomcat (non-spring boot) applications.

Solution2: Spring specific

You can disable the JarScanner for manifest files as below.

@Bean public EmbeddedServletContainerFactory embeddedServletContainerFactory() {   return new TomcatEmbeddedServletContainerFactory() {     @Override     protected void postProcessContext(Context context) {       ((StandardJarScanner) context.getJarScanner()).setScanManifest(false);     }   }; } 

Solution3 : Traditional Standalone Tomcat:

<Context>   ...   <JarScanner scanManifest="false"/>   ... </Context> 

Refer : The Jar Scanner Component.

Answer 2

Just to improve Sundaraj's findings... disabling TLD scanning completely will break JSP/JSTL support.

The issue is that the classpath itself is OK, only Tomcat additionally scans the manifest files of each Jar, and since with Maven each Jar is in its own directory, that generates meaningless paths (probably running from Eclipse?).

So if you want to keep using JSP with JSTL, you should disable just the manifest scanning.

For Spring Boot 2.0, add this to your application's configuration:

  @Bean   public TomcatServletWebServerFactory tomcatFactory() {     return new TomcatServletWebServerFactory() {       @Override       protected void postProcessContext(Context context) {         ((StandardJarScanner) context.getJarScanner()).setScanManifest(false);       }     };   }