updated dependencies + JDK16 compatibility.

updated maven dependencies
 - guice 5 can be used again without the noaop tag on latest jdks
 - asm, spring, lucene, velocity etc
updated webjars
 - bootstrap 3.4.1 is the last version before 4.x which comes with breaking changes
checked JDK16 compatibility
 - required war plugin update in selenium pom
diff --git a/app/pom.xml b/app/pom.xml
index fc76577..045f24e 100644
--- a/app/pom.xml
+++ b/app/pom.xml
@@ -39,26 +39,26 @@
         <java-mail.version>1.4.7</java-mail.version>
         <jstl.version>1.2</jstl.version>
         <angular.version>1.7.8</angular.version>
-        <ant.version>1.10.8</ant.version>
-        <asm.version>9.0-beta</asm.version>
+        <ant.version>1.10.9</ant.version>
+        <asm.version>9.1</asm.version>
         <commons-validator.version>1.7</commons-validator.version>
         <commons-beanutils.version>1.9.4</commons-beanutils.version>
         <commons-httpclient.version>3.1</commons-httpclient.version>
         <commons-codec.version>1.15</commons-codec.version>
-        <eclipse-link.version>2.7.7</eclipse-link.version>
-        <guice.version>4.2.3</guice.version>
-        <log4j2.version>2.13.3</log4j2.version>
-        <lucene.version>8.6.2</lucene.version>
+        <eclipse-link.version>2.7.8</eclipse-link.version>
+        <guice.version>5.0.1</guice.version>
+        <log4j2.version>2.14.1</log4j2.version>
+        <lucene.version>8.8.1</lucene.version>
         <oauth-core.version>20100527</oauth-core.version>
         <maven-war.version>3.2.3</maven-war.version>
-        <maven-surefire.version>2.17</maven-surefire.version>
+        <maven-surefire.version>2.22.2</maven-surefire.version>
         <maven-antrun.version>1.0b3</maven-antrun.version>
         <rome.version>1.15.0</rome.version>
         <slf4j.version>1.7.30</slf4j.version>
-        <spring.version>5.2.9.RELEASE</spring.version>
-        <spring.security.version>5.4.0</spring.security.version>
-        <struts.version>2.5.22</struts.version>
-        <velocity.version>2.2</velocity.version>
+        <spring.version>5.3.5</spring.version>
+        <spring.security.version>5.4.5</spring.security.version>
+        <struts.version>2.5.26</struts.version>
+        <velocity.version>2.3</velocity.version>
         <webjars.version>1.5</webjars.version>
         <ws-commons-util.version>1.0.2</ws-commons-util.version>
         <xml-security.version>1.3.0</xml-security.version>
@@ -251,23 +251,24 @@
             <artifactId>struts2-tiles-plugin</artifactId>
             <version>${struts.version}</version>
         </dependency>
-
+        
+        <!-- note: update head.jsp on webjar version change -->
         <dependency>
             <groupId>org.webjars</groupId>
             <artifactId>bootstrap</artifactId>
-            <version>3.3.7</version>
+            <version>3.4.1</version>
         </dependency>
 
         <dependency>
             <groupId>org.webjars</groupId>
             <artifactId>clipboard.js</artifactId>
-            <version>2.0.0</version>
+            <version>2.0.6</version>
         </dependency>
 
         <dependency>
             <groupId>org.webjars</groupId>
             <artifactId>jquery</artifactId>
-            <version>3.3.1</version>
+            <version>3.6.0</version>
         </dependency>
 
         <dependency>
@@ -279,13 +280,13 @@
         <dependency>
             <groupId>org.webjars.bower</groupId>
             <artifactId>summernote</artifactId>
-            <version>0.8.11</version>
+            <version>0.8.12</version>
         </dependency>
 
         <dependency>
             <groupId>org.webjars</groupId>
             <artifactId>jquery-validation</artifactId>
-            <version>1.19.0</version>
+            <version>1.19.3</version>
         </dependency>
 
         <dependency>
@@ -499,7 +500,6 @@
             <groupId>com.google.inject</groupId>
             <artifactId>guice</artifactId>
             <version>${guice.version}</version>
-            <classifier>no_aop</classifier>
             <exclusions>
                 <exclusion>
                     <groupId>aopalliance</groupId>
@@ -744,7 +744,7 @@
 
             <plugin>
                 <artifactId>maven-surefire-plugin</artifactId>
-                <version>2.22.0</version>
+                <version>${maven-surefire.version}</version>
                 <configuration>
                     <systemProperties>
                         <property>
diff --git a/app/src/main/webapp/WEB-INF/jsps/tiles/head.jsp b/app/src/main/webapp/WEB-INF/jsps/tiles/head.jsp
index 8a31d67..f205baf 100644
--- a/app/src/main/webapp/WEB-INF/jsps/tiles/head.jsp
+++ b/app/src/main/webapp/WEB-INF/jsps/tiles/head.jsp
@@ -5,21 +5,21 @@
 
 <%@ include file="/WEB-INF/jsps/taglibs-struts2.jsp" %>
 
-<script src="<s:url value='/webjars/jquery/3.3.1/jquery.min.js' />"></script>
+<script src="<s:url value='/webjars/jquery/3.6.0/jquery.min.js' />"></script>
 
 <script src="<s:url value='/webjars/jquery-ui/1.12.1/jquery-ui.min.js' />"></script>
 <link href="<s:url value='/webjars/jquery-ui/1.12.1/jquery-ui.css' />" rel="stylesheet" />
 
-<script src="<s:url value='/webjars/jquery-validation/1.19.0/jquery.validate.min.js' />"></script>
+<script src="<s:url value='/webjars/jquery-validation/1.19.3/jquery.validate.min.js' />"></script>
 
-<link href="<s:url value='/webjars/bootstrap/3.3.7/css/bootstrap.min.css' />" rel="stylesheet" />
-<link href="<s:url value='/webjars/bootstrap/3.3.7/css/bootstrap-theme.min.css' />" rel="stylesheet" />
-<script src="<s:url value='/webjars/bootstrap/3.3.7/js/bootstrap.min.js' />"></script>
+<link href="<s:url value='/webjars/bootstrap/3.4.1/css/bootstrap.min.css' />" rel="stylesheet" />
+<link href="<s:url value='/webjars/bootstrap/3.4.1/css/bootstrap-theme.min.css' />" rel="stylesheet" />
+<script src="<s:url value='/webjars/bootstrap/3.4.1/js/bootstrap.min.js' />"></script>
 
-<script src="<s:url value='/webjars/clipboard.js/2.0.0/clipboard.min.js' />"></script>
+<script src="<s:url value='/webjars/clipboard.js/2.0.6/clipboard.min.js' />"></script>
 
-<script src="<s:url value='/webjars/summernote/0.8.11/dist/summernote.min.js' />"></script>
-<link href="<s:url value='/webjars/summernote/0.8.11/dist/summernote.css' />" rel="stylesheet" />
+<script src="<s:url value='/webjars/summernote/0.8.12/dist/summernote.min.js' />"></script>
+<link href="<s:url value='/webjars/summernote/0.8.12/dist/summernote.css' />" rel="stylesheet" />
 
 <link rel="stylesheet" media="all" href='<s:url value="/roller-ui/styles/roller.css"/>' />
 
diff --git a/it-selenium/pom.xml b/it-selenium/pom.xml
index d2e7559..5c94bac 100644
--- a/it-selenium/pom.xml
+++ b/it-selenium/pom.xml
@@ -120,7 +120,14 @@
 
     <build>
         <plugins>
-
+            
+            <!-- bump plugin version for JDK 16 compatibility (old guice version),
+                 can be removed once maven itself bumped the version -->
+            <plugin>
+               <artifactId>maven-war-plugin</artifactId>
+               <version>3.3.1</version>
+            </plugin>
+             
             <!-- Activates integration tests (by default, classes under tests that end with "IT") -->
             <plugin>
                 <artifactId>maven-failsafe-plugin</artifactId>
diff --git a/pom.xml b/pom.xml
index 1269eb7..4f22568 100644
--- a/pom.xml
+++ b/pom.xml
@@ -92,7 +92,7 @@
                 <plugin>
                     <groupId>org.codehaus.mojo</groupId>
                     <artifactId>versions-maven-plugin</artifactId>
-                    <version>2.7</version>
+                    <version>2.8.1</version>
                     <configuration>
                         <rulesUri>file:version-rules.xml</rulesUri>
                     </configuration>
@@ -106,7 +106,7 @@
             <dependency>
                 <groupId>org.junit.jupiter</groupId>
                 <artifactId>junit-jupiter-engine</artifactId>
-                <version>5.6.2</version>
+                <version>5.7.1</version>
                 <scope>test</scope>
             </dependency>
         </dependencies>