Vahid Haratian Vahid Haratian - 3 months ago 33
Java Question

No Idea why : The ResourceConfig instance does not contain any root resource classes

i'm new to jersey and web services and i'm try to run a simple RESTful web service. i followed http://www.mkyong.com/webservices/jax-rs/jersey-hello-world-example/ but my project doesn't use maven and i download the jersey.1.17.1.jar and include it to my project path

when i want to call the service on

http://localhost:8080/sycotext/rest/service/SOMETEXT
i got this error :

HTTP Status 500 - Servlet.init() for servlet sycoText-servlet threw exception


this is the stack trace :

javax.servlet.ServletException: Servlet.init() for servlet sycoText-servlet threw exception
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:76)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:934)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:515)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1010)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:640)
org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1618)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1576)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
java.lang.Thread.run(Thread.java:724)

root cause

com.sun.jersey.api.container.ContainerException: The ResourceConfig instance does not contain any root resource classes.
com.sun.jersey.server.impl.application.RootResourceUriRules.<init>(RootResourceUriRules.java:99)
com.sun.jersey.server.impl.application.WebApplicationImpl._initiate(WebApplicationImpl.java:1331)
com.sun.jersey.server.impl.application.WebApplicationImpl.access$700(WebApplicationImpl.java:168)
com.sun.jersey.server.impl.application.WebApplicationImpl$13.f(WebApplicationImpl.java:774)
com.sun.jersey.server.impl.application.WebApplicationImpl$13.f(WebApplicationImpl.java:770)
com.sun.jersey.spi.inject.Errors.processWithErrors(Errors.java:193)
com.sun.jersey.server.impl.application.WebApplicationImpl.initiate(WebApplicationImpl.java:770)
com.sun.jersey.server.impl.application.WebApplicationImpl.initiate(WebApplicationImpl.java:765)
com.sun.jersey.spi.container.servlet.ServletContainer.initiate(ServletContainer.java:489)
com.sun.jersey.spi.container.servlet.ServletContainer$InternalWebComponent.initiate(ServletContainer.java:319)
com.sun.jersey.spi.container.servlet.WebComponent.load(WebComponent.java:605)
com.sun.jersey.spi.container.servlet.WebComponent.init(WebComponent.java:210)
com.sun.jersey.spi.container.servlet.ServletContainer.init(ServletContainer.java:374)
com.sun.jersey.spi.container.servlet.ServletContainer.init(ServletContainer.java:557)
javax.servlet.GenericServlet.init(GenericServlet.java:160)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:76)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:934)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:515)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1010)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:640)
org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1618)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1576)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
java.lang.Thread.run(Thread.java:724)


heare is my code :

package ir.sycotech.text.server.service;

import javax.ws.rs.*;
import javax.ws.rs.core.Response;

@Path("/service")
public class SycoTextService {
@GET
@Path("/{param}")
public Response getMsg(@PathParam("param") String msg) {
String output = "Jersey say : " + msg;
return Response.status(200).entity(output).build();
}


and here is my web.xml :

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

<display-name>Restful Web Application</display-name>


<servlet>
<servlet-name>sycoText-servlet</servlet-name>
<servlet-class>
com.sun.jersey.spi.container.servlet.ServletContainer
</servlet-class>
<init-param>
<param-name>com.sun.jersey.config.property.packages</param-name>
<param-value>ir.sycotech.text.server.service</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
<servlet-name>sycoText-servlet</servlet-name>
<url-pattern>/rest/*</url-pattern>
</servlet-mapping>

</web-app>


i have specified my packagename correctly in the web.xml file and i don't know why i got this error, i will be really appreciate if anyone knows what is the problem

Answer

The error:

com.sun.jersey.api.container.ContainerException: The ResourceConfig instance does not contain any root resource classes.

means that Jersey can't find service classes. That can be caused by a wrongly named package for the com.sun.jersey.config.property.packages parameter or if the package name is correct but it does not contain resource classes (people sometimes forget to add the @Path annotation on the class).

But I can't find anything wrong with your setup. So this should work!

Check that your application deployed correctly and that your WEB-INF/classes folder actually contains your class with the proper folder path for the package.

Do a full clean and rebuild then try again.