Log4j 删除问题

Question

I'm trying to remove Log4j from my project. The project is building sucessfully after removing but I'm getting this error while running the build.

org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/azuga]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162) 
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:755)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:731)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:717)
    at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:973)
    at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1850)
    at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at java.base/java.lang.Thread.run(Thread.java:834)
 Caused by: java.lang.NoClassDefFoundError: Lorg/apache/log4j/Logger;
    at java.base/java.lang.Class.getDeclaredFields0(Native Method)
    at java.base/java.lang.Class.privateGetDeclaredFields(Class.java:3062)
    at java.base/java.lang.Class.getDeclaredFields(Class.java:2249)
    at org.apache.catalina.util.Introspection.getDeclaredFields(Introspection.java:106)
    at org.apache.catalina.startup.WebAnnotationSet.loadFieldsAnnotation(WebAnnotationSet.java:269)
    at org.apache.catalina.startup.WebAnnotationSet.loadApplicationFilterAnnotations(WebAnnotationSet.java:109)
    at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:68)
    at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:336)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:776)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:307)
    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:5262)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
    ... 10 more
 Caused by: java.lang.ClassNotFoundException: org.apache.log4j.Logger
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1352)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1180)
    ... 24 more

I've tried removing dependencies I suspected to be using Log4j.

Answer 1

As a general advice, use a tool to manage your project's dependencies such as Gradle or Maven. These tools are capable of analyzing not only classpath dependencies but also runtime dependencies. That way, you can just see what the dependencies are - rather than suspecting.