Question

I am trying to implement recoemmender code in java dynamic web application using direct approach. i can compile the code but when i run the application on server i am getting following error:

type
Exception report

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

exception
javax.servlet.ServletException: Servlet execution threw an exception

root cause
java.lang.NoClassDefFoundError: org/apache/mahout/cf/taste/model/DataModel
com.demoMahout.HelperRecommender.getUserBasedRecommendation(HelperRecommender.java:96)
com.demoMahout.HelperRecommender.doPost(HelperRecommender.java:53)
javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

root cause
java.lang.ClassNotFoundException: org.apache.mahout.cf.taste.model.DataModel
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1676)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1521)
java.lang.ClassLoader.loadClassInternal(ClassLoader.java:332)
com.demoMahout.HelperRecommender.getUserBasedRecommendation(HelperRecommender.java:96)
com.demoMahout.HelperRecommender.doPost(HelperRecommender.java:53)
javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
javax.servlet.http.HttpServlet.service(HttpServlet.java:722)

How can i resolve this issue?

Answer 1

It means just what it says: you don’t have the Mahout classes included in your web app! put the JAR files in WEB-INF/lib as you need to do with any other library a web app needs.