Hello Prabhat,
Try to remove xmlns:s="#unknown" from the jsp, and also ensure that following taglib directive is present in your page.
<%@ taglib prefix="s" uri="/struts-tags" %>
Ensure that the filter is defined in web.xml as shown below (
From the sample it's not clear)
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
This definition should appear before the welcome-file-list element.
Please also ensure that the struts jar is present in WEB-INF/lib folder.
Regards,