diff --git a/.github/workflows/github-actions-build.yml b/.github/workflows/github-actions-build.yml
index 2c93ad6..f33869b 100755
--- a/.github/workflows/github-actions-build.yml
+++ b/.github/workflows/github-actions-build.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ '8', '11', '17' ]
+        java: [ '17' ]
 
     name: Java ${{ matrix.Java }} build with Maven
     env:
@@ -46,7 +46,7 @@ jobs:
         uses: actions/setup-java@v3
         with:
           distribution: 'adopt'
-          java-version: '11'
+          java-version: '17'
       - name: Coverage with Jacoco Maven plugin
         run: mvn verify jacoco:report --quiet --batch-mode -DbuildNumber=${GITHUB_RUN_NUMBER}
       - uses: codecov/codecov-action@v1
diff --git a/Dockerfile b/Dockerfile
index 164c233..9b8556c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,7 +1,5 @@
-# java:8 is 600M+, alpine < 200M
-# FROM java:8
-
-FROM adoptopenjdk/openjdk11:alpine-slim
+# java:8 containers are 600M+, alpine < 200M
+FROM openjdk/17-jdk-slim
 
 EXPOSE 8080
 COPY target/spring-boot-example-1.0-SNAPSHOT.jar /app.jar
diff --git a/pom.xml b/pom.xml
index 96bc55b..8e851c5 100755
--- a/pom.xml
+++ b/pom.xml
@@ -10,7 +10,7 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>2.7.8</version>
+        <version>3.0.5</version>
     </parent>
 
     <description>Simple Spring Boot app to get started.</description>
@@ -68,12 +68,12 @@
         <dependency>
             <groupId>org.webjars</groupId>
             <artifactId>bootstrap</artifactId>
-            <version>3.3.7</version>
+            <version>3.4.0</version>
         </dependency>
         <dependency>
             <groupId>org.webjars</groupId>
             <artifactId>jquery</artifactId>
-            <version>1.12.4</version>
+            <version>3.6.2</version>
         </dependency>
 
         <!-- user agent analysis -->
@@ -86,8 +86,8 @@
         <!-- Swagger for api documentation -->
         <dependency>
             <groupId>org.springdoc</groupId>
-            <artifactId>springdoc-openapi-ui</artifactId>
-            <version>1.7.0</version>
+            <artifactId>springdoc-openapi-starter-webmvc-ui</artifactId>
+            <version>2.1.0</version>
         </dependency>
 
         <!-- below for robot framework -->
@@ -238,7 +238,7 @@
             <plugin>
                 <groupId>org.jacoco</groupId>
                 <artifactId>jacoco-maven-plugin</artifactId>
-                <version>0.8.5</version>
+                <version>0.8.9</version>
                 <executions>
                     <execution>
                         <goals>
diff --git a/src/main/java/example/counter/CounterRequest.java b/src/main/java/example/counter/CounterRequest.java
index 59d665c..bd9f6d3 100644
--- a/src/main/java/example/counter/CounterRequest.java
+++ b/src/main/java/example/counter/CounterRequest.java
@@ -1,6 +1,6 @@
 package example.counter;
 
-import javax.validation.constraints.NotNull;
+import jakarta.validation.constraints.NotNull;
 
 import lombok.Data;
 
diff --git a/src/main/java/example/counter/CounterRestController.java b/src/main/java/example/counter/CounterRestController.java
index b36fec5..b8cded3 100755
--- a/src/main/java/example/counter/CounterRestController.java
+++ b/src/main/java/example/counter/CounterRestController.java
@@ -1,6 +1,6 @@
 package example.counter;
 
-import javax.validation.Valid;
+import jakarta.validation.Valid;
 
 import io.swagger.v3.oas.annotations.Operation;
 import org.springframework.http.MediaType;
@@ -12,7 +12,7 @@
 
 @RestController
 @RequestMapping(
-        produces = MediaType.APPLICATION_JSON_UTF8_VALUE,
+        produces = MediaType.APPLICATION_JSON_VALUE,
         consumes = MediaType.APPLICATION_JSON_VALUE)
 public class CounterRestController {
     public static final String ADD_URL = "/counter/add";
diff --git a/src/main/resources/static/css/counter-style.css b/src/main/resources/static/css/counter-style.css
index a77e5cb..1ce7266 100755
--- a/src/main/resources/static/css/counter-style.css
+++ b/src/main/resources/static/css/counter-style.css
@@ -1,17 +1,14 @@
-* {
+body {
     background-color: #eee;
 }
 .vertical-center {
-    min-height: 100%;  /* Fallback for browsers do NOT support vh unit */
+    min-height: 100%;  /* Fallback for browsers who do NOT support vh unit */
     min-height: 100vh; /* These two lines are counted as one :-)       */
 
     display: flex;
     flex-direction: column;
     justify-content: center;
 }
-.container {
-    width: 100%;
-}
 #result {
     border: solid #dadada 2px;
     padding: 2px;
diff --git a/src/main/resources/templates/counter.html b/src/main/resources/templates/counter.html
index 1a546cf..47bdf16 100755
--- a/src/main/resources/templates/counter.html
+++ b/src/main/resources/templates/counter.html
@@ -6,14 +6,28 @@
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <meta http-equiv="X-UA-Compatible" content="IE=edge" />
     <link rel="stylesheet" type="text/css"
-          href="/webjars/bootstrap/3.3.7/css/bootstrap.min.css" />
+          href="/webjars/bootstrap/3.4.0/css/bootstrap.min.css" />
     <link href="/css/counter-style.css" rel="stylesheet" />
-    <script type="text/javascript" src="/webjars/jquery/1.12.4/jquery.min.js"></script>
-    <script type="text/javascript" src="/webjars/bootstrap/3.3.7/js/bootstrap.min.js"></script>
+    <script type="text/javascript" src="/webjars/jquery/3.6.2/jquery.min.js"></script>
+    <script type="text/javascript" src="/webjars/bootstrap/3.4.0/js/bootstrap.min.js"></script>
     <script type="text/javascript" src="/js/counter.js"></script>
 </head>
 <body>
-    <div class="container vertical-center text-center">
+    <nav class="navbar navbar-inverse">
+        <div class="container">
+            <div class="navbar-header">
+                <a class="navbar-brand" href="https://projects.spring.io/spring-boot/">Spring Boot</a>
+            </div>
+            <div id="navbar" class="collapse navbar-collapse">
+                <ul class="nav navbar-nav">
+                    <li><a href="/">Home</a></li>
+                    <li class="active"><a href="/counter">Counter</a></li>
+                </ul>
+            </div>
+        </div>
+    </nav>
+
+    <div class="container vertical-center text-center" id="main">
         <form class="form-inline">
             <div class="form-group">
                 <label class="sr-only" for="inputFirst">First number</label>
diff --git a/src/main/resources/templates/greeting.html b/src/main/resources/templates/greeting.html
index 7bf71c3..dccb62b 100755
--- a/src/main/resources/templates/greeting.html
+++ b/src/main/resources/templates/greeting.html
@@ -5,44 +5,40 @@
     <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
 
     <link rel="stylesheet" type="text/css"
-          href="/webjars/bootstrap/3.3.7/css/bootstrap.min.css" />
+          href="/webjars/bootstrap/3.4.0/css/bootstrap.min.css" />
 
     <link rel="stylesheet" th:href="@{/css/greeting-style.css}"
           href="/css/greeting-style.css" />
 
 </head>
 <body>
+    <nav class="navbar navbar-inverse">
+        <div class="container">
+            <div class="navbar-header">
+                <a class="navbar-brand" href="https://projects.spring.io/spring-boot/">Spring Boot</a>
+            </div>
+            <div id="navbar" class="collapse navbar-collapse">
+                <ul class="nav navbar-nav">
+                    <li class="active"><a href="/">Home</a></li>
+                    <li><a href="/counter">Counter</a></li>
+                </ul>
+            </div>
+        </div>
+    </nav>
 
-<nav class="navbar navbar-inverse">
     <div class="container">
-        <div class="navbar-header">
-            <a class="navbar-brand" href="https://projects.spring.io/spring-boot/">Spring Boot</a>
-        </div>
-        <div id="navbar" class="collapse navbar-collapse">
-            <ul class="nav navbar-nav">
-                <li class="active"><a href="#">Home</a></li>
-                <li><a href="#about">About</a></li>
-            </ul>
+        <div class="starter-template">
+            <h1>Spring Boot Web Thymeleaf Example</h1>
+            <h2>
+                <span th:text="'Hello, ' + ${subject} + '!'"></span>
+            </h2>
         </div>
     </div>
-</nav>
-
-<div class="container">
-
-    <div class="starter-template">
-        <h1>Spring Boot Web Thymeleaf Example</h1>
-        <h2>
-            <span th:text="'Hello, ' + ${subject} + '!'"></span>
-        </h2>
-    </div>
-
-</div>
-<!-- /.container -->
 
-<script type="text/javascript"
-        src="/webjars/jquery/1.12.4/jquery.min.js"></script>
-<script type="text/javascript"
-        src="/webjars/bootstrap/3.3.7/js/bootstrap.min.js"></script>
+    <script type="text/javascript"
+            src="/webjars/jquery/3.6.2/jquery.min.js"></script>
+    <script type="text/javascript"
+            src="/webjars/bootstrap/3.4.0/js/bootstrap.min.js"></script>
 
 </body>
 </html>
\ No newline at end of file
diff --git a/src/test/java/example/counter/CounterRequestTest.java b/src/test/java/example/counter/CounterRequestTest.java
index 72acfda..b21d468 100755
--- a/src/test/java/example/counter/CounterRequestTest.java
+++ b/src/test/java/example/counter/CounterRequestTest.java
@@ -3,10 +3,10 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import javax.validation.ConstraintViolation;
-import javax.validation.Validation;
-import javax.validation.Validator;
-import javax.validation.ValidatorFactory;
+import jakarta.validation.ConstraintViolation;
+import jakarta.validation.Validation;
+import jakarta.validation.Validator;
+import jakarta.validation.ValidatorFactory;
 import java.util.Set;
 
 import static org.junit.Assert.assertFalse;
diff --git a/ubuntu-deps.sh b/ubuntu-deps.sh
index 3a0c0d9..b1c2f14 100755
--- a/ubuntu-deps.sh
+++ b/ubuntu-deps.sh
@@ -1,2 +1,2 @@
 apt-get update
-apt-get install -y openjdk-8-jdk maven
+apt-get install -y openjdk-17-jdk maven