Eclipse - Java.Lang.Classnotfoundexception: Org.Springframework.Web.Servlet.Dispatcherservlet Inwards Tomcat

Problem : You are getting java.lang.ClassNotFoundException exception complaining that Spring's DispatcherServlet class is non available inwards the classpath. This mistake is coming spell running a Spring MVC based Java application from Eclipse together with Tomcat equally Server (running within Eclipse IDE itself). You receive got either included saltation framework JAR files manually past times yourself or you lot are using Maven to download together with contend subject JAR files. Here is the stack draw of this mistake :

java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1678)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1523)
    at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:525)
    at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:507)
    at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:126)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1099)
    at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1043)
    at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4957

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

There are 2 primary create of getting java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet mistake inwards Eclipse :

1) First, either you lot don't receive got spring-webmvc-3.1.0.RELEASE.jar or like JAR, depending upon which Spring framework version you lot are using e.g. Spring 4.0

2) Second is, Eclipse is non able to detect this dependency inwards CLASSPATH.


But earlier going into those, let's starting fourth dimension understand
what is org.springframework.web.servlet.DispatcherServlet class? together with why it is required?.

This shape is genuinely the forepart controller inwards Spring MVC framework, all HTTP requests acquire via this shape to dissimilar controller classes. You define this shape to map against a URL blueprint inwards the web.xml file using load-on-startup tag, that's why you lot come across that loadOnStartup() call on stack trace of this error. 


This is why when you lot deploy your Spring MVC based spider web application inwards Tomcat, the WebAppClassLoader search for org.springframework.web.servlet.DispatcherServlet shape inwards shape loader's CLASSPATH, which is WEB-INF/lib folder of your Java Web application.


If it doesn't flora this shape within whatsoever JAR file inwards WEB-INF/lib, it throws java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet.


If you lot are novel to Spring, you lot tin too accept a hold off at Spring inwards Action book, 1 of the ameliorate books to larn basics of Spring framework together with Spring MVC together. The quaternary edition of this majority too covers Spring 4.

Now let's come across how to solve this problem.

How to Fix java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet inwards Tomcat together with Eclipse

Here are merely about steps you lot tin accept to bargain amongst this mistake inwards Tomcat within Eclipse IDE :

1) If you lot are using Maven together with if spring-webmvc is non added equally a dependency inwards your project's pom.xml thence delight add together that. Once you lot produce that, create your projection using mvn install or mvn build. This volition download saltation MVC JAR files together with merely about other dependency.


2) The minute measurement is to add together Maven Dependency into deployment assembly. This is required to motion all subject JAR files into WEB-INF/lib directory of Java spider web application.

In lodge to add together Maven Dependency into deployment assembly inwards Eclipse, follow below steps :

i) Right-click your project, select properties together with pick out Deployment Assembly.

ii)  Now click Add together with pick out Java Build Path Entries together with select Maven dependency theirs. If your projection is non laid for the automatic create thence merely refresh the projection together with create it.

Now you lot should move able to run your Spring MVC application inwards attached Tomcat from Eclipse IDE itself.

3) If this doesn't prepare your work thence produce a Maven clean, followed past times Maven create to regenerate WAR file.


That's all close how to prepare java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet mistake inwards Eclipse together with Tomcat. It's too possible that you lot acquire this mistake exterior Eclipse IDE when you lot are deploying your WAR file inwards merely about other environment. That fourth dimension you lot must depository fiscal establishment gibe whether relevant JAR file e.g. spring-webmvc-3.1.0.RELEASE.jar exists inwards either WEB-INF/lib directory of your application or Tomcat/lib directory. It's ameliorate to choke on inwards WEB-INF/lib directory because when you lot undeploy all the classes loaded past times WebAppClassLoader are eligible for garbage collection, which is non the representative for JAR files loaded from Tomcat's lib directory. That tin create PermGen Memory leak inwards Tomcat.

Further Reading
Spring Framework 5: Beginner to Guru
Spring Master Class - Beginner to Expert
Introduction to Spring MVC 4 By Bryan Hansen
Spring together with Hibernate for Beginners
Spring inwards Action 4th edition past times Craig Walls

P.S. - If you lot desire to larn how to prepare RESTful Web Service using Spring MVC inwards depth, I advise you lot bring together the REST amongst Spring certification class past times Eugen Paraschiv. One of the best course of teaching to larn REST amongst Spring MVC. 

Sumber https://javarevisited.blogspot.com/

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