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I have a relatively simple project that uploads a zip file to a servlet, however, when POST to the servlet I suddenly started getting the following error:

500 Internal Server Error

Servlet error: Error instantiating servlet 'ConfirmSiteReport'. Servlet class uploader.ConfirmSiteReport not found in web-application SiteReport-Uploader-webapp

I've checked the web.xml and have not found anything wrong, and I dont recall changing anything in the project config when this error started, and the class file is in the classes directory.:
<servlet>
<servlet-name>ConfirmSiteReport</servlet-name>
<servlet-class>uploader.ConfirmSiteReport</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ConfirmSiteReport</servlet-name>
<url-pattern>/confirmsitereport</url-pattern>
</servlet-mapping>