Ndtyjky

Please don't flag this post as a duplicate one because I didn't find any good resource in the relevant question.

Technologies used :-
Spring MVC 4.3.3.RELEASE
Gradle 3.1
Tomcat 9.0

I created a dynamic web project and when I run it, I get the following error

HTTP Status 500 - Error instantiating servlet class org.springframework.web.servlet.DispatcherServlet



type Exception report



message Error instantiating servlet class org.springframework.web.servlet.DispatcherServlet



description The server encountered an internal error that prevented it from fulfilling this request.



exception



javax.servlet.ServletException: Error instantiating servlet class org.springframework.web.servlet.DispatcherServlet

    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:522)

    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)

    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)

    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)

    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:1102)

    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)

    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:788)

    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1485)

    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

    java.lang.Thread.run(Thread.java:745)

root cause



java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet

    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1299)

    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1133)

    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:522)

    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)

    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)

    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)

    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:1102)

    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)

    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:788)

    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1485)

    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)

    java.lang.Thread.run(Thread.java:745)

It is saying that it could not find the dispatcher servlet class but when I ctrl + click the dispatcher servlet path in the spring-dispatcher-servlet , It lands to the spring Dispatcher Servlet class. I could not get the root cause of this problem.

Here are my web.xml and spring-dispatcher-servlet.xml files

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_3_1.xsd" id="WebApp_ID" version="3.1">

  <display-name>MenuOrder</display-name>



  <welcome-file-list>

    <welcome-file>index.jsp</welcome-file>

  </welcome-file-list>



  <servlet>

    <servlet-name>spring-dispatcher</servlet-name>

    <servlet-class>

        org.springframework.web.servlet.DispatcherServlet

    </servlet-class>

  </servlet>



  <servlet-mapping>

    <servlet-name>spring-dispatcher</servlet-name>

    <url-pattern>/</url-pattern>

  </servlet-mapping>



</web>

spring-dispatcher-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>



<beans xmlns="http://www.springframework.org/schema/beans"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation="http://www.springframework.org/schema/beans 

    http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">



    <bean id = "HandlerMapping" class = "org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"/>



    <bean id = "viewResolver" 

        class = "org.springframework.web.servlet.view.InternalResourceViewResolver">

        <property name = "prefix">

            <value>/WEB-INF/</value>

        </property>



        <property name = "sufix">

            <value>.jsp</value>

        </property>

        </bean>



</beans>

Project directory

My gradle.build file

allprojects{

apply plugin: 'java'

apply plugin: 'eclipse-wtp'

group = 'com'

version = '0.0.1-SNAPSHOT'

}



subprojects{

    tasks.withType(JavaCompile){

    options.encoding = 'UTF-8'

    }

}







allprojects {

    task hello { task -> println "I'm $task.project.name" }

}





allprojects{



repositories {

    mavenLocal()

    jcenter()

    mavenCentral()



}





    dependencies {



        // The production code uses the SLF4J logging API at compile time

    //    compile 'org.slf4j:slf4j-api:1.7.21'





        //spring web

        compile group: 'org.springframework', name: 'spring-webmvc', version: '4.3.3.RELEASE'



        // spring core

        compile group: 'org.springframework', name: 'spring-core', version: '4.3.3.RELEASE'



        // spring context support

        compile group: 'org.springframework', name: 'spring-context-support', version: '4.3.3.RELEASE'





        // ORM dependencies



        // spring jpa

        compile group: 'org.springframework.data', name: 'spring-data-jpa', version: '1.10.4.RELEASE'



        // hibernate-entity manager

        compile group: 'org.hibernate', name: 'hibernate-entitymanager', version: '5.2.2.Final'



        // End of ORM dependencies



        // postgres connector

        compile group: 'org.postgresql', name: 'postgresql', version: '9.4-1200-jdbc41'



        // Junit

        compile group: 'junit', name: 'junit', version: '4.12'



        // servlet

        compile group: 'javax.servlet', name: 'javax.servlet-api', version: '4.0.0-b01'



        compile group: 'javax.el', name: 'javax.el-api', version: '2.2.1'



        compile group: 'org.springframework', name: 'spring', version: '3.2.0.RC1'



        }

        }

The whole project code can be found in
https://github.com/viper-pranish/menu-order

Dependencies inside the project structure

you can simply add tag under tag of web.xml, It will work.

as @Denium pointed out you should not mix the spring versions

remove compile group: 'org.springframework', name: 'spring', version: '3.2.0.RC1' from gradle.build
and add

apply plugin: 'war'

and you may to provide your controller url mapping as well

<bean name="/index"

            class="com.mkyong.common.controller.IndexController" />

Make sure that you have added all the required Spring jars at both places:
in build path as well as WEB-INF/lib folder

<dependencies>

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-webmvc</artifactId>

            <version>4.1.7.RELEASE</version>

            <exclusions>

                <exclusion>

                    <artifactId>commons-logging</artifactId>

                    <groupId>commons-logging</groupId>

                </exclusion>

            </exclusions>

        </dependency>

        <dependency>

            <groupId>javax.servlet</groupId>

            <artifactId>jstl</artifactId>

            <version>1.2</version>

        </dependency>





        <dependency>

            <groupId>junit</groupId>

            <artifactId>junit</artifactId>

            <version>4.12</version>

        </dependency>



        <dependency>

            <groupId>org.slf4j</groupId>

            <artifactId>jcl-over-slf4j</artifactId>

            <version>1.7.12</version>

        </dependency>



        <dependency>

            <groupId>org.springframework.security</groupId>

            <artifactId>spring-security-web</artifactId>

            <version>4.0.2.RELEASE</version>

        </dependency>

        <dependency>

            <groupId>org.springframework.security</groupId>

            <artifactId>spring-security-config</artifactId>

            <version>4.0.2.RELEASE</version>

        </dependency>

        <dependency>

            <groupId>org.springframework.security</groupId>

            <artifactId>spring-security-taglibs</artifactId>

            <version>4.0.2.RELEASE</version>

        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-web</artifactId>

            <version>4.1.7.RELEASE</version>

        </dependency>



    </dependencies>

1. Add slf4j dependencies. The problem will resolve. My pom.xml dependencies it resolved the problem.




2. After adding slf4j if the problem is not resolved, then add Maven Dependency in Deployment Assembly.