From 4ad9dc05cf9cc18f6adebeb6f061cb43d61a3168 Mon Sep 17 00:00:00 2001
From: Miles Mason Winther <42948872+mmwinther@users.noreply.github.com>
Date: Wed, 3 Jul 2024 14:48:23 +0200
Subject: [PATCH] Explicitly deregister JDBC driver (#181)

* Explicitly deregister JDBC driver

* Remove first solution attempt
---
 klass-forvaltning/pom.xml                     | 20 ++++---------
 .../klass/KlassForvaltningApplication.java    | 30 +++++++++++++++++--
 2 files changed, 33 insertions(+), 17 deletions(-)

diff --git a/klass-forvaltning/pom.xml b/klass-forvaltning/pom.xml
index 4c5c035..74610fa 100644
--- a/klass-forvaltning/pom.xml
+++ b/klass-forvaltning/pom.xml
@@ -85,26 +85,12 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-tomcat</artifactId>
             <scope>provided</scope>
-            <exclusions>
-                <exclusion>
-                    <!-- Potential cause of DPMETA-287 -->
-                    <groupId>org.apache.tomcat</groupId>
-                    <artifactId>tomcat-jdbc</artifactId>
-                </exclusion>
-            </exclusions>
         </dependency>
 
         <dependency>
             <groupId>org.apache.tomcat.embed</groupId>
             <artifactId>tomcat-embed-jasper</artifactId>
             <scope>provided</scope>
-            <exclusions>
-                <exclusion>
-                    <!-- Potential cause of DPMETA-287 -->
-                    <groupId>org.apache.tomcat</groupId>
-                    <artifactId>tomcat-jdbc</artifactId>
-                </exclusion>
-            </exclusions>
         </dependency>
 
         <!--VAADIN-->
@@ -198,6 +184,12 @@
             <artifactId>assertj-core</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>jakarta.servlet</groupId>
+            <artifactId>jakarta.servlet-api</artifactId>
+            <version>4.0.4</version>
+            <scope>compile</scope>
+        </dependency>
     </dependencies>
 
     <dependencyManagement>
diff --git a/klass-forvaltning/src/main/java/no/ssb/klass/KlassForvaltningApplication.java b/klass-forvaltning/src/main/java/no/ssb/klass/KlassForvaltningApplication.java
index 1f71c8d..f56833a 100644
--- a/klass-forvaltning/src/main/java/no/ssb/klass/KlassForvaltningApplication.java
+++ b/klass-forvaltning/src/main/java/no/ssb/klass/KlassForvaltningApplication.java
@@ -7,19 +7,43 @@
 import org.springframework.boot.web.support.SpringBootServletInitializer;
 import org.springframework.context.annotation.Import;
 
-// CHECKSTYLE:OFF
+import javax.servlet.ServletContext;
+import javax.servlet.ServletContextEvent;
+import javax.servlet.ServletContextListener;
+import javax.servlet.ServletException;
+
+
 @SpringBootApplication
 @Import(EmbeddedServletContainerAutoConfiguration.EmbeddedTomcat.class)
 public class KlassForvaltningApplication extends SpringBootServletInitializer {
-    // TODO kmgv if using embedded container (e.g. Tomcat) remove below method and extends SpringBootServletInitializer
+
     @Override
     protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
         return application.sources(KlassForvaltningApplication.class);
     }
 
+    @Override
+    public void onStartup(ServletContext servletContext) throws ServletException {
+        servletContext.addListener(new ServletContextListener() {
+
+            @Override
+            public void contextInitialized(ServletContextEvent servletContextEvent) {
+                // Nothing to do here
+            }
+
+            @Override
+            public void contextDestroyed(ServletContextEvent sce) {
+                // Explicitly deregister the driver to prevent race conditions with Tomcat de-registering the Driver.
+                // This is fixed in Spring Boot versions >=2.3.0
+                // Ref https://github.com/spring-projects/spring-boot/issues/21221
+                org.mariadb.jdbc.Driver.unloadDriver();
+            }
+        });
+        super.onStartup(servletContext);
+    }
+
 
     public static void main(String[] args) {
         SpringApplication.run(KlassForvaltningApplication.class, args);
     }
 }
-// CHECKSTYLE:ON
\ No newline at end of file