Every filter defined in web.xml
file should be used in a <filter-mapping>
element. Otherwise such filters are not
invoked.
<filter> <filter-name>DefinedNotUsed</filter-name> <filter-class>com.myco.servlet.ValidationFilter</filter-class> </filter>
<filter> <filter-name>ValidationFilter</filter-name> <filter-class>com.myco.servlet.ValidationFilter</filter-class> </filter> <filter-mapping> <filter-name>ValidationFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>