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How to fix java.lang.NoSuchMethodException: Servlets.MyServlet.<init>() at java.base/java.lang.Class.getConstructor0

I have a form in a jsp page that I'm trying to connect to a servlet, MyServlet. I am using Tomcat 10.x. I keep getting the following error:

HTTP Status 500 – Internal Server Error

Type Exception Report

Message Error instantiating servlet class [Servlets.MyServlet]

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

Exception

jakarta.servlet.ServletException: Error instantiating servlet class [Servlets.MyServlet]
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:482)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:673)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:340)
    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:391)
    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:896)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1744)
    org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
    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:1589)
Root Cause

java.lang.NoSuchMethodException: Servlets.MyServlet.<init>()
    java.base/java.lang.Class.getConstructor0(Class.java:3641)
    java.base/java.lang.Class.getConstructor(Class.java:2324)
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:482)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93)
    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:673)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:340)
    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:391)
    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:896)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1744)
    org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
    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:1589)
Note The full stack trace of the root cause is available in the server logs.

Apache Tomcat/10.1.18

I understand that it is not finding the servlet in the given location(?), but I'm not sure what to do to fix the issue. Any help would be greatly appreciated.

Here are my files:

File hierarchy image

index.jsp

<html>
<body>
<h2>Hello World!</h2>
<form action="MyServlet" method="get">
    <input type="submit" value="Enter">
</form>
</body>
</html>

MyServlet.java

package Servlets;

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;

@WebServlet("/MyServlet")
public class MyServlet extends HttpServlet {

    MyServlet(){
        super();
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }
}

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>org.example</groupId>
  <artifactId>BaseProject</artifactId>
  <packaging>war</packaging>
  <version>1.0-SNAPSHOT</version>
  <name>BaseProject Maven Webapp</name>
  <url>http://maven.apache.org</url>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>jakarta.servlet</groupId>
      <artifactId>jakarta.servlet-api</artifactId>
      <version>6.0.0</version>
      <scope>provided</scope>
    </dependency>
  </dependencies>
  <build>
    <finalName>BaseProject</finalName>
  </build>
</project>

I tried removing '@WebServlet("/MyServlet")' from MyServlet.java and manually adding the servlet and servlet mapping to the web.xml as follows:

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>
  
  <servlet>
    <servlet-name>MyServlet</servlet-name>
    <servlet-class>Servlets.MyServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>MyServlet</servlet-name>
    <url-pattern>/MyServlet</url-pattern>
  </servlet-mapping>

</web-app>

However, this still resulted in the 500 error.

Solution

  • Make the servlet's constructor public so that it can be run by Tomcat.

    public MyServlet() {
    super();
}