At 23:00 yesterday, an error was reported after an old project was packaged and released to the cloud server. Tomcat9 couldn’t start, which wasted me several hours.

This error has been encountered before and has been forgotten for a long time. It is hereby recorded

Error log

22-Dec-2021 23:52:18.703 SEVERE [main] org.apache.catalina.startup.HostConfig.deployWAR Error deploying web application archive [/usr/tomcat/webapps/project.war]
    java.lang.IllegalStateException: Error starting child
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:731)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:700)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:696)
        at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:1024)
        at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1911)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
        at java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:112)
        at org.apache.catalina.startup.HostConfig.deployWARs(HostConfig.java:825)
        at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:475)
        at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1618)
        at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:319)
        at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:123)
        at org.apache.catalina.util.LifecycleBase.setStateInternal(LifecycleBase.java:423)
        at org.apache.catalina.util.LifecycleBase.setState(LifecycleBase.java:366)
        at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:948)
        at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:835)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1388)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
        at java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:134)
        at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:921)
        at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:263)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
        at org.apache.catalina.core.StandardService.startInternal(StandardService.java:437)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
        at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:934)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
        at org.apache.catalina.startup.Catalina.start(Catalina.java:772)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:345)
        at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:476)
    Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/project]]
        at org.apache.catalina.util.LifecycleBase.handleSubClassException(LifecycleBase.java:440)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:198)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:728)
        ... 37 more

process

My environment is centenos7 + tomcat9 + jdk8 + springboot2*

After reporting the error, I checked a lot of information on the Internet, and a variety of solutions emerge one after another

But it’s not egg, as usual nonsense.

On the Internet

1. It’s said to change Java_ A configuration related to random numbers under JRE/lib under home (changed, useless)

2. It’s said to change the Tomcat Version (never tried, trouble)

3. It’s said to change C. under Tomcat conf So and so configuration file (useless at first sight)

4. Some people say that the JDK is low (mine is 1.8, so it’s impossible)

5. It is said that the version of the spring * * * framework is inconsistent with the relevant environment (as long as it can run in the editor, it generally does not exist)

5. A reliable post: Tomcat/conf/server The item corresponding to the docbase attribute of the context node under the host node in XML is wrong (this is possible, but mine is OK)

Solution:

Empty the target folder, pack again, publish, success!