diff --git a/servlet/java-configuration/aspectj/build.gradle b/servlet/java-configuration/aspectj/build.gradle
index a0e3469..de33190 100644
--- a/servlet/java-configuration/aspectj/build.gradle
+++ b/servlet/java-configuration/aspectj/build.gradle
@@ -21,7 +21,7 @@ dependencies {
 
 	runtime "org.springframework.security:spring-security-aspects"
 
-	testImplementation "org.assertj:assertj-core:3.15.0"
+	testImplementation "org.assertj:assertj-core:3.18.0"
 	testImplementation "org.springframework:spring-test"
 	testImplementation "org.springframework.security:spring-security-test"
 	testImplementation "org.junit.jupiter:junit-jupiter-api"
diff --git a/servlet/java-configuration/authentication/username-password/form/build.gradle b/servlet/java-configuration/authentication/username-password/form/build.gradle
index 6329eae..f322ae8 100644
--- a/servlet/java-configuration/authentication/username-password/form/build.gradle
+++ b/servlet/java-configuration/authentication/username-password/form/build.gradle
@@ -22,7 +22,7 @@ dependencies {
 	implementation "org.springframework:spring-webmvc"
 	implementation "org.thymeleaf:thymeleaf-spring5:3.0.11.RELEASE"
 
-	testImplementation "org.assertj:assertj-core:3.15.0"
+	testImplementation "org.assertj:assertj-core:3.18.0"
 	testImplementation "org.springframework:spring-test"
 	testImplementation "org.springframework.security:spring-security-test"
 	testImplementation("org.junit.jupiter:junit-jupiter-api")
diff --git a/servlet/java-configuration/data/build.gradle b/servlet/java-configuration/data/build.gradle
index 83b0a86..ecee2f9 100644
--- a/servlet/java-configuration/data/build.gradle
+++ b/servlet/java-configuration/data/build.gradle
@@ -25,7 +25,7 @@ dependencies {
 	implementation 'org.hsqldb:hsqldb:2.5.1'
 	implementation 'org.springframework.data:spring-data-jpa'
 
-	testImplementation "org.assertj:assertj-core:3.15.0"
+	testImplementation "org.assertj:assertj-core:3.18.0"
 	testImplementation "org.springframework:spring-test"
 	testImplementation "org.springframework.security:spring-security-test"
 	testImplementation("org.junit.jupiter:junit-jupiter-api")
diff --git a/servlet/java-configuration/hello-mvc-security/build.gradle b/servlet/java-configuration/hello-mvc-security/build.gradle
index 6329eae..f322ae8 100644
--- a/servlet/java-configuration/hello-mvc-security/build.gradle
+++ b/servlet/java-configuration/hello-mvc-security/build.gradle
@@ -22,7 +22,7 @@ dependencies {
 	implementation "org.springframework:spring-webmvc"
 	implementation "org.thymeleaf:thymeleaf-spring5:3.0.11.RELEASE"
 
-	testImplementation "org.assertj:assertj-core:3.15.0"
+	testImplementation "org.assertj:assertj-core:3.18.0"
 	testImplementation "org.springframework:spring-test"
 	testImplementation "org.springframework.security:spring-security-test"
 	testImplementation("org.junit.jupiter:junit-jupiter-api")
diff --git a/servlet/java-configuration/hello-security-explicit/build.gradle b/servlet/java-configuration/hello-security-explicit/build.gradle
index 6dce579..b8ece36 100644
--- a/servlet/java-configuration/hello-security-explicit/build.gradle
+++ b/servlet/java-configuration/hello-security-explicit/build.gradle
@@ -25,7 +25,7 @@ dependencies {
 	providedCompile "javax.servlet:javax.servlet-api:4.0.1"
 	providedCompile "javax.servlet.jsp:javax.servlet.jsp-api:2.3.3"
 
-	testImplementation "org.assertj:assertj-core:3.15.0"
+	testImplementation "org.assertj:assertj-core:3.18.0"
 	testImplementation "org.springframework:spring-test"
 	testImplementation "org.springframework.security:spring-security-test"
 	testImplementation("org.junit.jupiter:junit-jupiter-api")
diff --git a/servlet/java-configuration/hello-security/build.gradle b/servlet/java-configuration/hello-security/build.gradle
index 6dce579..b8ece36 100644
--- a/servlet/java-configuration/hello-security/build.gradle
+++ b/servlet/java-configuration/hello-security/build.gradle
@@ -25,7 +25,7 @@ dependencies {
 	providedCompile "javax.servlet:javax.servlet-api:4.0.1"
 	providedCompile "javax.servlet.jsp:javax.servlet.jsp-api:2.3.3"
 
-	testImplementation "org.assertj:assertj-core:3.15.0"
+	testImplementation "org.assertj:assertj-core:3.18.0"
 	testImplementation "org.springframework:spring-test"
 	testImplementation "org.springframework.security:spring-security-test"
 	testImplementation("org.junit.jupiter:junit-jupiter-api")
diff --git a/servlet/java-configuration/max-sessions/build.gradle b/servlet/java-configuration/max-sessions/build.gradle
index 6329eae..f322ae8 100644
--- a/servlet/java-configuration/max-sessions/build.gradle
+++ b/servlet/java-configuration/max-sessions/build.gradle
@@ -22,7 +22,7 @@ dependencies {
 	implementation "org.springframework:spring-webmvc"
 	implementation "org.thymeleaf:thymeleaf-spring5:3.0.11.RELEASE"
 
-	testImplementation "org.assertj:assertj-core:3.15.0"
+	testImplementation "org.assertj:assertj-core:3.18.0"
 	testImplementation "org.springframework:spring-test"
 	testImplementation "org.springframework.security:spring-security-test"
 	testImplementation("org.junit.jupiter:junit-jupiter-api")