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Question

HTTP Status 500 – Internal Server Error
Type Exception Report

Message Error instantiating servlet class [com.demo.servletprg.MyServlet]

Description The server encountered an unexpected condition that prevented it from fulfilling the request.

Exception

jakarta.servlet.ServletException: Error instantiating servlet class [com.demo.servletprg.MyServlet]
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:356)
    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)
    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:870)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1762)
    org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
    org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.base/java.lang.Thread.run(Thread.java:1583)
Root Cause

java.lang.ClassNotFoundException: com.demo.servletprg.MyServlet
    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1449)
    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1257)
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:356)
    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399)
    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:870)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1762)
    org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
    org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.base/java.lang.Thread.run(Thread.java:1583)
Note The full stack trace of the root cause is available in the server logs.

index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>sample sevlet</title>
</head>
<body>
 <h1 style="color:red">welcome to my page</h1>
 <a href="/Servletprograms/MyServlet"> click here to view MyServlet </a>
</body>
</html>

myservlet.code
package com.demo.servletprg;

import jakarta.servlet.ServletException;
import jakarta.servlet.annotation.WebServlet;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

/**
 * Servlet implementation class MyServlet
 */
public class MyServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public MyServlet() {
        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
        response.getWriter().append("Served at: ").append(request.getContextPath());
        PrintWriter out=response.getWriter();
        response.setContentType("text/html");
        out.println("<br><h1 style=color:green>"+"Welcome To My Servlet"+"</h1>");
    }

}

Apache Tomcat/10.0.27enter image description here

I’m encountering an issue with my Java web application deployed on Apache Tomcat. When I try to access a servlet, I’m getting an “HTTP Status 500 – Internal Server Error” with the message “Error instantiating servlet class [com.demo.servletprg.MyServlet]”. The root cause of this error is a “java.lang.ClassNotFoundException” `for the servlet class.

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Danh mục

Getting “java.lang.ClassNotFoundException” for Servlet Class in Apache Tomcat