BAEL-305: Updated servlet spec to 3.1.

enterprise-patterns/front-controller-pattern/pom.xml

@@ -17,7 +17,7 @@
         <dependency>
             <groupId>javax.servlet</groupId>
             <artifactId>javax.servlet-api</artifactId>
-            <version>4.0.0-b01</version>
+            <version>3.1.0</version>
             <scope>provided</scope>
         </dependency>
     </dependencies>

enterprise-patterns/front-controller-pattern/src/main/webapp/WEB-INF/web.xml

@@ -1,5 +1,9 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<web-app xmlns="http://java.sun.com/xml/ns/javaee" version="2.5">
+<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
+		   http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
+         version="3.1">
     <servlet>
         <servlet-name>front-controller</servlet-name>
         <servlet-class>com.baeldung.enterprise.patterns.front.controller.FrontControllerServlet</servlet-class>