It is not finding the controllers, this is basic issues.
it can be due to following reasons.
A. inside WEB-INF folder you have file web.xml that refers to dispatcherServlet. Here it this case is mvc-config.xml
<servlet>
    <servlet-name>dispatcherServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/mvc-config.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>
B. This mvc-config.xml file have namespaces and it has to scan the controllers.
<context:component-scan base-package="org.vimal.spring.controllers" />
<mvc:annotation-driven />
C.  Check for the correctness of the package name where you have the controllers. It should work. 
All Controllers must be Annotated with @Controller.