Class missing during startup but available afterwards - spring

Question

I'm migrating a project from old Ant scripts to Gradle. For development, I'm using gradle-tomcat-plugin, and the java and war plugins.
The project gets built in a Docker container, which works fine for me but not for my colleague. When he runs gradle tomcatRun, he gets an error like this:
A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost].StandardContext[/rsa]]
at java.util.concurrent.FutureTask.report(FutureTask.java:122)
at java.util.concurrent.FutureTask.get(FutureTask.java:192)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:816)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1575)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1565)
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)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost].StandardContext[/rsa]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
... 6 more
Caused by: java.lang.NoClassDefFoundError: ServletException
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
at java.lang.Class.getDeclaredMethods(Class.java:1975)
at org.apache.catalina.util.Introspection.getDeclaredMethods(Introspection.java:127)
at org.apache.catalina.startup.WebAnnotationSet.loadMethodsAnnotation(WebAnnotationSet.java:287)
at org.apache.catalina.startup.WebAnnotationSet.loadApplicationServletAnnotations(WebAnnotationSet.java:140)
at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:65)
at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:415)
at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:892)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:386)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5412)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 6 more
Caused by: java.lang.ClassNotFoundException: ServletException
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1720)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1571)
... 20 more
A child container failed during start
I assume this is referring to javax.servlet.ServletException. However, if I force one of the servlets to throw a ServletException (which I can test because it loads fine on my machine), it can find that class with no problem.
My build file looks something like this (full source here):
providedCompile (
"org.apache.tomcat:tomcat-catalina:$tomcatVersion",
)
compile (
'com.googlecode.lambdaj:lambdaj:2.3.3',
'com.sun.xml.bind:jaxb-impl:2.1',
'commons-io:commons-io:1.3.2',
'commons-net:commons-net:3.4',
'javax.validation:validation-api:1.0.0.GA',
'org.codehaus.jackson:jackson-mapper-asl:1.7.1',
'org.hibernate:hibernate-validator:4.2.0.Final',
"org.springframework:org.springframework.web:$springVersion",
"org.springframework:org.springframework.web.servlet:$springVersion",
'rome:rome:1.0',
)
runtime (
'commons-fileupload:commons-fileupload:1.2',
"org.springframework:spring-oxm:$springVersion",
)
tomcat (
"org.apache.tomcat.embed:tomcat-embed-core:$tomcatVersion",
"org.apache.tomcat.embed:tomcat-embed-logging-juli:$tomcatVersion",
"org.apache.tomcat.embed:tomcat-embed-jasper:$tomcatVersion",
)
Is there another ServletException that I'm missing a .jar for? Or is it that the .jar might not have loaded during server startup, but gets loaded later? The app is currently configured to use servlet API 2.4. I've seen some other threads saying to upgrade it, but changing it to 2.5 didn't help.
build.gradle
web.xml
Dockerfile

Answer 1

OK this is embarrassing: there must have been some stale files hiding in my colleague's source tree, maybe masked by .gitignore. Doing a clean checkout of the repository has "fixed" the problem.
I say "fixed" because we never really got to the bottom of it: the error was saying that it couldn't find ServletException. I implemented my own ServletException in the default package (thanks Thilo for the tip), but it just showed another similar error. Anyway it works now, so chances are it was just a classpath problem involving a file that shouldn't have been in the source tree.