에러 : java.lang.ClassCastException: class java.io.ObjectStreamClass$Caches$1 cannot be cast to class java.util.Map (java.io.ObjectStreamClass$Caches$1 and java.util.Map are in module java.base of loader 'bootstrap')

경고: 웹 애플리케이션 [ROOT]을(를) 위해, ObjectStreamClass$Caches로부터 soft references를 폐기하지 못했습니다.
java.lang.ClassCastException: class java.io.ObjectStreamClass$Caches$1 cannot be cast to class java.util.Map (java.io.ObjectStreamClass$Caches$1 and java.util.Map are in module java.base of loader 'bootstrap')
	at org.apache.catalina.loader.WebappClassLoaderBase.clearCache(WebappClassLoaderBase.java:2325)
	at org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesObjectStreamClassCaches(WebappClassLoaderBase.java:2300)
	at org.apache.catalina.loader.WebappClassLoaderBase.clearReferences(WebappClassLoaderBase.java:1669)
	at org.apache.catalina.loader.WebappClassLoaderBase.stop(WebappClassLoaderBase.java:1597)
	at org.apache.catalina.loader.WebappLoader.stopInternal(WebappLoader.java:463)
	at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:257)
	at org.apache.catalina.core.StandardContext.stopInternal(StandardContext.java:5515)
	at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:257)
	at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3811)
	at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:311)
	at org.apache.catalina.core.StandardContext.backgroundProcess(StandardContext.java:5613)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1365)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1369)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1369)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1347)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
	at java.base/java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305)
	at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.base/java.lang.Thread.run(Thread.java:840)

JSP 구동중에 이런 에러가 발생했다.

[해결방안]

import 부분에 pojo1이 공통으로 포함되어있었다.

전부 다 제거하니 오류가 해결됐다.