diff --git a/patterns/src/main/java/com/baeldung/patterns/filters/AuthenticationFilter.java b/patterns/src/main/java/com/baeldung/patterns/filters/AuthenticationFilter.java
index fa7655434e..f5e03878ca 100644
--- a/patterns/src/main/java/com/baeldung/patterns/filters/AuthenticationFilter.java
+++ b/patterns/src/main/java/com/baeldung/patterns/filters/AuthenticationFilter.java
@@ -3,22 +3,23 @@ package com.baeldung.patterns.filters;
 import com.baeldung.patterns.commands.FrontCommand;
 import com.baeldung.patterns.commands.LoginCommand;
 
-import javax.servlet.FilterChain;
-import javax.servlet.ServletException;
-import javax.servlet.ServletRequest;
-import javax.servlet.ServletResponse;
+import javax.servlet.*;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
 import java.io.IOException;
 
-public class AuthenticationFilter extends BaseFilter {
+public class AuthenticationFilter implements Filter {
     private OnIntercept callback;
 
     public AuthenticationFilter(OnIntercept callback) {
         this.callback = callback;
     }
 
+    @Override
+    public void init(FilterConfig filterConfig) throws ServletException {
+    }
+
     @Override
     public void doFilter(
       ServletRequest request,
@@ -37,4 +38,8 @@ public class AuthenticationFilter extends BaseFilter {
             chain.doFilter(request, response);
         }
     }
+
+    @Override
+    public void destroy() {
+    }
 }
diff --git a/patterns/src/main/java/com/baeldung/patterns/filters/EncodingFilter.java b/patterns/src/main/java/com/baeldung/patterns/filters/EncodingFilter.java
index 1277ca726d..2856bb1112 100644
--- a/patterns/src/main/java/com/baeldung/patterns/filters/EncodingFilter.java
+++ b/patterns/src/main/java/com/baeldung/patterns/filters/EncodingFilter.java
@@ -2,9 +2,13 @@ package com.baeldung.patterns.filters;
 
 import javax.servlet.*;
 import javax.servlet.annotation.WebFilter;
+import javax.servlet.annotation.WebInitParam;
 import java.io.IOException;
 
-@WebFilter(servletNames = "front-controller")
+@WebFilter(
+  servletNames = {"front-controller"},
+  initParams = {@WebInitParam(name = "encoding", value = "UTF-8")}
+)
 public class EncodingFilter extends BaseFilter {
     private String encoding;
 
diff --git a/patterns/src/main/java/com/baeldung/patterns/filters/FilterChainImpl.java b/patterns/src/main/java/com/baeldung/patterns/filters/FilterChainImpl.java
index d2b64c7d06..789fc003a0 100644
--- a/patterns/src/main/java/com/baeldung/patterns/filters/FilterChainImpl.java
+++ b/patterns/src/main/java/com/baeldung/patterns/filters/FilterChainImpl.java
@@ -1,14 +1,11 @@
 package com.baeldung.patterns.filters;
 
-import javax.servlet.Filter;
-import javax.servlet.ServletException;
-import javax.servlet.ServletRequest;
-import javax.servlet.ServletResponse;
+import javax.servlet.*;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Iterator;
 
-public class FilterChainImpl implements javax.servlet.FilterChain {
+public class FilterChainImpl implements FilterChain {
     private Iterator<Filter> filters;
 
     public FilterChainImpl(Filter... filters) {
diff --git a/patterns/src/main/java/com/baeldung/patterns/filters/TemplateFilter.java b/patterns/src/main/java/com/baeldung/patterns/filters/TemplateFilter.java
new file mode 100644
index 0000000000..939d9ad84d
--- /dev/null
+++ b/patterns/src/main/java/com/baeldung/patterns/filters/TemplateFilter.java
@@ -0,0 +1,35 @@
+package com.baeldung.patterns.filters;
+
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+public abstract class TemplateFilter extends BaseFilter {
+
+    protected abstract void preFilter(
+      HttpServletRequest request,
+      HttpServletResponse response
+    ) throws IOException, ServletException;
+
+    protected abstract void postFilter(
+      HttpServletRequest request,
+      HttpServletResponse response
+    ) throws IOException, ServletException;
+
+    @Override
+    public void doFilter(
+      ServletRequest request,
+      ServletResponse response,
+      FilterChain chain
+    ) throws IOException, ServletException {
+        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
+        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
+        preFilter(httpServletRequest, httpServletResponse);
+        chain.doFilter(request, response);
+        postFilter(httpServletRequest, httpServletResponse);
+    }
+}
diff --git a/patterns/src/main/java/com/baeldung/patterns/filters/VisitorCounterFilter.java b/patterns/src/main/java/com/baeldung/patterns/filters/VisitorCounterFilter.java
index 0abfac7cd6..5c2358686b 100644
--- a/patterns/src/main/java/com/baeldung/patterns/filters/VisitorCounterFilter.java
+++ b/patterns/src/main/java/com/baeldung/patterns/filters/VisitorCounterFilter.java
@@ -1,18 +1,19 @@
 package com.baeldung.patterns.filters;
 
-import javax.servlet.FilterChain;
-import javax.servlet.ServletException;
-import javax.servlet.ServletRequest;
-import javax.servlet.ServletResponse;
+import javax.servlet.*;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpSession;
 import java.io.IOException;
 import java.util.HashSet;
 import java.util.Set;
 
-public class VisitorCounterFilter extends BaseFilter {
+public class VisitorCounterFilter implements Filter {
     private static Set<String> users = new HashSet<>();
 
+    @Override
+    public void init(FilterConfig filterConfig) throws ServletException {
+    }
+
     @Override
     public void doFilter(
       ServletRequest request,
@@ -21,10 +22,12 @@ public class VisitorCounterFilter extends BaseFilter {
     ) throws IOException, ServletException {
         HttpSession session = ((HttpServletRequest) request).getSession(false);
         String username = (String) session.getAttribute("username");
-        if (!users.contains(username)) {
-            users.add(username);
-        }
+        users.add(username);
         request.setAttribute("counter", users.size());
         chain.doFilter(request, response);
     }
+
+    @Override
+    public void destroy() {
+    }
 }
diff --git a/patterns/src/main/resources/front controller.png b/patterns/src/main/resources/front_controller.png
similarity index 100%
rename from patterns/src/main/resources/front controller.png
rename to patterns/src/main/resources/front_controller.png
diff --git a/patterns/src/main/resources/front controller.puml b/patterns/src/main/resources/front_controller.puml
similarity index 100%
rename from patterns/src/main/resources/front controller.puml
rename to patterns/src/main/resources/front_controller.puml
diff --git a/patterns/src/main/resources/intercepting_filter.png b/patterns/src/main/resources/intercepting_filter.png
new file mode 100644
index 0000000000..9ccacc8081
Binary files /dev/null and b/patterns/src/main/resources/intercepting_filter.png differ
diff --git a/patterns/src/main/resources/intercepting_filter.puml b/patterns/src/main/resources/intercepting_filter.puml
new file mode 100644
index 0000000000..b06b822323
--- /dev/null
+++ b/patterns/src/main/resources/intercepting_filter.puml
@@ -0,0 +1,17 @@
+@startuml
+scale 1.5
+
+class Client
+class FilterManager
+interface FilterChain
+interface "Filter 1"
+interface "Filter 2"
+interface "Filter 3"
+
+Client .right.-- FilterManager
+FilterManager .right.-- Target
+FilterManager -- FilterChain
+FilterChain .right.-- "Filter 3"
+FilterChain .right.-- "Filter 2"
+FilterChain .right.-- "Filter 1"
+@enduml