例外処理エラー ページが表示され、エラー コードは 404 [クローズ済み]

org.apache.catalina.core.StandardHostValve custom
SEVERE: Exception Processing ErrorPage[errorCode=404, location=/error]
javax.servlet.ServletException: Error instantiating servlet class com.shashi.servlets.ErrorHandlerServlet
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1123)
    at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:827)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:694)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:468)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:391)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:318)
    at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:433)
    at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:299)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:176)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1085)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
    at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1556)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1513)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Thread.java:1570)
Caused by: java.lang.ClassNotFoundException: com.shashi.servlets.ErrorHandlerServlet
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1295)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1147)
    at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:520)
    at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:501)
    at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:120)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1105)
    ... 21 more