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POJersey REST The ResourceConfig instance does not contain any root resource classes
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  1. POJersey REST The ResourceConfig instance does not contain any root resource classes
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    copied!<p>Although this is one ancient question, I still can not find the answer to make this work. Please correct if you find any of my statement is not correct.</p> <p>I have a Java Face app and use REST for the Web Services. I don't think Face has anything to do with my problem at all. The web.xml is:</p> <pre><code>&lt;servlet&gt; &lt;servlet-name&gt;NDREST&lt;/servlet-name&gt; &lt;servlet-class&gt; com.sun.jersey.spi.container.servlet.ServletContainer &lt;/servlet-class&gt; &lt;init-param&gt; &lt;param-name&gt;com.sun.jersey.config.property.packages&lt;/param-name&gt; &lt;param-value&gt;com.bi.nd.webservice&lt;/param-value&gt; &lt;/init-param&gt; &lt;load-on-startup&gt;1&lt;/load-on-startup&gt; &lt;/servlet&gt; &lt;servlet-mapping&gt; &lt;servlet-name&gt;NDREST&lt;/servlet-name&gt; &lt;url-pattern&gt;/nd/*&lt;/url-pattern&gt; &lt;/servlet-mapping&gt; </code></pre> <p>I have quite a few more servlets in the web.xml since is is a Face app with Trinidad, etc.</p> <p>In the package com.bi.nd.webservice, my resource class is:</p> <pre><code>import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBElement; import javax.xml.bind.Marshaller; import javax.ws.rs.Consumes; import javax.ws.rs.GET; import javax.ws.rs.POST; import javax.ws.rs.Path; import javax.ws.rs.Produces; import javax.ws.rs.core.MediaType; @Produces(MediaType.APPLICATION_XML) @Path("/hello") public class TransactionResource { public TransactionResource() { } @GET @Produces(MediaType.TEXT_PLAIN) public String itWorks() { return "Get is OK"; } } </code></pre> <p>The fact that my class has a @GET is enough to identify itself a resource class.<br> Let alone all other complexities, I compiled my source code with Ant in Eclipse and I got this error in the catalina.out file:</p> <pre><code>May 24, 2011 8:48:46 AM com.sun.jersey.api.core.PackagesResourceConfig init INFO: Scanning for root resource and provider classes in the packages: com.bi.nd.webservice May 24, 2011 8:48:46 AM com.sun.jersey.server.impl.application.WebApplicationImpl _initiate INFO: Initiating Jersey application, version 'Jersey: 1.7 05/20/2011 11:04 AM' May 24, 2011 8:48:46 AM com.sun.jersey.server.impl.application.RootResourceUriRules &lt;init&gt; SEVERE: The ResourceConfig instance does not contain any root resource classes. </code></pre> <p>Some suggested that copy the asm.jar, jsr-api.jar, jersey-server.jar and jersey-core.jar into the app WEB-INF/lib. I did that and it still did not work. I found the suggestion was a bit odd since WEB-INF/lib is a place where Eclipse will install all dependency libraries from the build path. It is not a place where we manually put libraries.</p> <p>Some explained that this error had something to do with Java plug-in and the way Jersey was written. But that was years ago.</p> <p>Can some one explains to me why I keep having this problem?</p> <p>Followup: Although from REST web site, resource class defined as Root resource classes are POJOs (Plain Old Java Objects) that are either annotated with@Path or have at least one method annotated with @Path or a request method designator such as @GET, @PUT, @POST, or @DELETE. Resource methods are methods of a resource class annotated with a request method designator. This section describes how to use Jersey to annotate Java objects to create RESTful web services.</p> <p>I have to add @Path("/hello") to my class, and suddenly Jersey can find my resource class</p> <p>Now the catalina.out file looks like:</p> <pre><code>May 24, 2011 3:13:02 PM com.sun.jersey.api.core.PackagesResourceConfig init INFO: Scanning for root resource and provider classes in the packages: com.bi.nd.webservice May 24, 2011 3:13:02 PM com.sun.jersey.api.core.ScanningResourceConfig logClasses INFO: Root resource classes found: class com.bi.nd.webservice.TransactionResource May 24, 2011 3:13:02 PM com.sun.jersey.api.core.ScanningResourceConfig init INFO: No provider classes found. May 24, 2011 3:13:02 PM com.sun.jersey.server.impl.application.WebApplicationImpl _initiate INFO: Initiating Jersey application, version 'Jersey: 1.7 05/20/2011 11:04 AM' </code></pre> <p>But the problem is far from over. I try to access the URL <code>http://localhost:8080/nd/hello</code> and I still get the 404 NOT FOUND. Is the Provider class NOT FOUND an important message?</p>
 

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