Eclipse tomcat java.lang.ClassNotFoundException: com.web.servlets.SearchServiceServlet

Question

Tomcat throws exception java.lang.ClassNotFoundException: com.web.servlets.SearchServiceServlet every time i try to access my servlet. The servlets is in the correct package structure:

I defined my servlet in the web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" id="WebApp_ID" version="4.0">
  <display-name>PetClinic</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>

  <session-config>
    <session-timeout>15</session-timeout>
  </session-config>

  <servlet>
    <servlet-name>searchService</servlet-name>
    <servlet-class>com.web.servlets.SearchServiceServlet</servlet-class>
  </servlet>

 <servlet-mapping>
    <servlet-name>searchService</servlet-name>
    <url-pattern>/searchServ</url-pattern>
 </servlet-mapping>

</web-app>

The servlet class:

public class SearchServiceServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public SearchServiceServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        String first_name = request.getParameter("first_name");
        String last_name = request.getParameter("last_name");
        int age = Integer.valueOf( request.getParameter("age") );
        String pet_name = request.getParameter("pet_Name");
        String pet_type = request.getParameter("pet_type");
        int rating = Integer.valueOf(request.getParameter("rating"));
        int experience = Integer.valueOf(request.getParameter("experience"));

        System.out.println("First name = "+first_name+",last name = "+last_name+",age = "+age+",pet's name = "+pet_name+",pet's type = "+pet_type+",rating = "+rating+",experience = "+experience);
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

Could it be that eclipse doesn't properly generate classes?If yes,how can i test this?Because a simple POJO with main method works fine.

Also,here is the full exception and what the tomcat prints when i start the application:

апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Server version name:   Apache Tomcat/9.0.17
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Server built:          Mar 13 2019 15:55:27 UTC
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Server version number: 9.0.17.0
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: OS Name:               Windows 10
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: OS Version:            10.0
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Architecture:          amd64
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Java Home:             C:\Program Files\Java\jdk1.8.0_181\jre
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: JVM Version:           1.8.0_181-b13
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: JVM Vendor:            Oracle Corporation
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: CATALINA_BASE:         C:\Users\Barracuda\Desktop\Projects\Eclipse Projects\.metadata\.plugins\org.eclipse.wst.server.core\tmp0
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: CATALINA_HOME:         C:\Program Files\Apache Software Foundation\Tomcat 9.0
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Dcatalina.base=C:\Users\Barracuda\Desktop\Projects\Eclipse Projects\.metadata\.plugins\org.eclipse.wst.server.core\tmp0
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Dcatalina.home=C:\Program Files\Apache Software Foundation\Tomcat 9.0
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Dwtp.deploy=C:\Users\Barracuda\Desktop\Projects\Eclipse Projects\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Djava.endorsed.dirs=C:\Program Files\Apache Software Foundation\Tomcat 9.0\endorsed
апр 11, 2019 12:15:21 PM org.apache.catalina.startup.VersionLoggerListener log
INFO: Command line argument: -Dfile.encoding=Cp1251
апр 11, 2019 12:15:21 PM org.apache.catalina.core.AprLifecycleListener lifecycleEvent
INFO: An older version [1.2.17] of the APR based Apache Tomcat Native library is installed, while Tomcat recommends a minimum version of [1.2.21]
апр 11, 2019 12:15:21 PM org.apache.catalina.core.AprLifecycleListener lifecycleEvent
INFO: Loaded APR based Apache Tomcat Native library [1.2.17] using APR version [1.6.3].
апр 11, 2019 12:15:21 PM org.apache.catalina.core.AprLifecycleListener lifecycleEvent
INFO: APR capabilities: IPv6 [true], sendfile [true], accept filters [false], random [true].
апр 11, 2019 12:15:21 PM org.apache.catalina.core.AprLifecycleListener lifecycleEvent
INFO: APR/OpenSSL configuration: useAprConnector [false], useOpenSSL [true]
апр 11, 2019 12:15:22 PM org.apache.catalina.core.AprLifecycleListener initializeSSL
INFO: OpenSSL successfully initialized [OpenSSL 1.0.2o  27 Mar 2018]
апр 11, 2019 12:15:22 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-nio-8080"]
апр 11, 2019 12:15:23 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["ajp-nio-8009"]
апр 11, 2019 12:15:23 PM org.apache.catalina.startup.Catalina load
INFO: Server initialization in [2 666] milliseconds
апр 11, 2019 12:15:23 PM org.apache.catalina.core.StandardService startInternal
INFO: Starting service [Catalina]
апр 11, 2019 12:15:23 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet engine: [Apache Tomcat/9.0.17]
апр 11, 2019 12:15:23 PM org.apache.jasper.servlet.TldScanner scanJars
INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
апр 11, 2019 12:15:24 PM org.apache.jasper.servlet.TldScanner scanJars
INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
апр 11, 2019 12:15:24 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-nio-8080"]
апр 11, 2019 12:15:24 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-nio-8009"]
апр 11, 2019 12:15:24 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in [987] milliseconds
апр 11, 2019 12:15:28 PM org.apache.catalina.core.ApplicationContext log
INFO: Marking servlet [searchService] as unavailable
апр 11, 2019 12:15:28 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Allocate exception for servlet [searchService]
java.lang.ClassNotFoundException: com.web.servlets.SearchServiceServlet
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1363)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1186)
    at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:540)
    at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:521)
    at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:150)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1031)
    at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:761)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:134)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:834)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1415)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

P.S The class is in the right package :package com.web.servlets;

Answer 1

The problem got fixed after the restart of eclipse...Though there is another problem. Whenever i save the servlets class,after changing it,it doesn't see the new class,but uses the previous version of it.What's the problem here?

Answer 2

java.lang.ClassNotFoundException Exception is thrown when the ClassLoader cannot find the specified class.

You have:

<servlet-class>com.web.servlets.SearchServiceServlet</servlet-class>

That means you have a package: com.web.servlets where the class SearchServiceServlet is located.

In case you have a Maven project you should have scr/main/java/%yourpackagename%/yourClass In case it is a simple web-project then it should be like src/yourpackagename/yourClass.

Answer 3

Try specifying the package in your class file.

 package com.web.servlets;