Jersey : The ResourceConfig instance does not contain any root resource classes

When you are working with Jersey REST web services, you would encounter the following exception. This is occurred either of two reasons.

1. com.sun.jersey.config.property.packages doesn’t exist in your web.xml.
2. com.sun.jersey.config.property.packages included a package path, but that is not included any jersey services.

If you check the above two reasons and resolve it, the below exception will be resolved.

[code]
com.sun.jersey.api.container.ContainerException: The ResourceConfig instance does not contain any root resource classes.
at com.sun.jersey.server.impl.application.RootResourceUriRules.
<init>(RootResourceUriRules.java:99)
at com.sun.jersey.server.impl.application.WebApplicationImpl.
_initiate(WebApplicationImpl.java:1331)
at com.sun.jersey.server.impl.application.WebApplicationImpl.access$700
(WebApplicationImpl.java:168)
at com.sun.jersey.server.impl.application.WebApplicationImpl$13.f
(WebApplicationImpl.java:774)
at com.sun.jersey.server.impl.application.WebApplicationImpl$13.f
(WebApplicationImpl.java:770)
at com.sun.jersey.spi.inject.Errors.processWithErrors(Errors.java:193)
at com.sun.jersey.server.impl.application.WebApplicationImpl.initiate
(WebApplicationImpl.java:770)
at com.sun.jersey.server.impl.application.WebApplicationImpl.initiate
(WebApplicationImpl.java:765)
at com.sun.jersey.spi.container.servlet.ServletContainer.initiate
(ServletContainer.java:489)
at com.sun.jersey.spi.container.servlet.ServletContainer$InternalWebComponent.
initiate(ServletContainer.java:319)
at com.sun.jersey.spi.container.servlet.WebComponent.load(WebComponent.java:605)
at com.sun.jersey.spi.container.servlet.WebComponent.init(WebComponent.java:210)
at com.sun.jersey.spi.container.servlet.ServletContainer.
init(ServletContainer.java:374)
at com.sun.jersey.spi.container.servlet.ServletContainer.
init(ServletContainer.java:557)
at javax.servlet.GenericServlet.init(GenericServlet.java:212)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1173)
at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:993)
at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4149)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4458)
at org.apache.catalina.core.StandardContext.reload(StandardContext.java:3190)
at org.apache.catalina.loader.WebappLoader.backgroundProcess(WebappLoader.java:404)
at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1309)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.
processChildren(ContainerBase.java:1601)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.
processChildren(ContainerBase.java:1610)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.
processChildren(ContainerBase.java:1610)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.
run(ContainerBase.java:1590)
at java.lang.Thread.run(Unknown Source)
[/code]

The web.xml file would look like this:

web.xml

[code lang=”xml”]
<servlet>
<servlet-name>jersey-serlvet</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>javabeat.net.jersey</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
<servlet-name>jersey-serlvet</servlet-name>
<url-pattern>/rest/*</url-pattern>
</servlet-mapping>
[/code]