Error instantiating servlet class 'com.telusko.AddServlet'

Question

I am trying to run my app on tomcat server.

In web.xml, I have given the correct classname for my servlet which resides in the package com.telusko

Still, it says error instatiating class'com.telusko.AddServlet' , noclassfoundexception Please help Error

File structure :(https://i.stack.imgur.com/XnZqG.png)

<?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">

 <servlet>
<servlet-name>abc</servlet-name>
<servlet-class>com.telusko.AddServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>abc</servlet-name>
<url-pattern>/add</url-pattern>
</servlet-mapping>

</web-app>

Answer 1

My suggestion is that you can try using the below 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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <properties>
        <maven.compiler.source>11</maven.compiler.source>
        <maven.compiler.target>11</maven.compiler.target>
    </properties>
    
<dependencies>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
</dependencies>
 
  <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>3.3.1</version>
            </plugin>
            
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
            </plugin>

        </plugins>
    </build>
  <version>1.0-RELEASE</version>
  <packaging>war</packaging>
</project>

and you can use the web servlet annotation and extend the HttpServlet class in the java class,

@WebServlet("/login")
public class LoginServlet extends HttpServlet {