HTTP Status 500

Question

HTTP Status 500 - Error instantiating servlet class com.imooc.servlet.SmartDownloadServlettype Exception reportmessage Error instantiating servlet class com.imooc.servlet.SmartDownloadServletdescription The server encountered an internal error that prevented it from fulfilling this request.exception javax.servlet.ServletException: Error instantiating servlet class com.imooc.servlet.SmartDownloadServlet org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99) org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953) org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408) org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023) org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589) org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1852) java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) java.lang.Thread.run(Thread.java:745) root cause java.lang.ClassNotFoundException: com.imooc.servlet.SmartDownloadServlet org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1714) org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559) org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502) org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99) org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953) org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408) org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023) org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589) org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1852) java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) java.lang.Thread.run(Thread.java:745) note The full stack trace of the root cause is available in the Apache Tomcat/7.0.42 logs 

Answer 1

错误是没有找到com.imooc.servlet.SmartDownloadServletz这个类

Answer 2

java代码有错误