diff --git a/core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedDevModeMain.java b/core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedDevModeMain.java
index 745e6a94317b2..25ef8e28951fd 100644
--- a/core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedDevModeMain.java
+++ b/core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedDevModeMain.java
@@ -321,6 +321,8 @@ public void close() {
                         RuntimeUpdatesProcessor.INSTANCE.close();
                     } catch (IOException e) {
                         log.error("Failed to close compiler", e);
+                    } finally {
+                        RuntimeUpdatesProcessor.INSTANCE = null;
                     }
                 }
                 for (HotReplacementSetup i : hotReplacementSetups) {
diff --git a/core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedRemoteDevModeMain.java b/core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedRemoteDevModeMain.java
index 4eb1f162bbf56..b01dce10be579 100644
--- a/core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedRemoteDevModeMain.java
+++ b/core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedRemoteDevModeMain.java
@@ -176,6 +176,8 @@ public void close() {
                 RuntimeUpdatesProcessor.INSTANCE.close();
             } catch (IOException e) {
                 log.error("Failed to close compiler", e);
+            } finally {
+                RuntimeUpdatesProcessor.INSTANCE = null;
             }
             for (HotReplacementSetup i : hotReplacementSetups) {
                 i.close();
diff --git a/core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedTestModeMain.java b/core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedTestModeMain.java
index dce3eb0cfc3cb..e58029cd79cf2 100644
--- a/core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedTestModeMain.java
+++ b/core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedTestModeMain.java
@@ -90,6 +90,8 @@ public void close() {
                 RuntimeUpdatesProcessor.INSTANCE.close();
             } catch (IOException e) {
                 e.printStackTrace();
+            } finally {
+                RuntimeUpdatesProcessor.INSTANCE = null;
             }
             for (HotReplacementSetup i : hotReplacementSetups) {
                 i.close();
diff --git a/core/deployment/src/main/java/io/quarkus/deployment/dev/testing/TestSupport.java b/core/deployment/src/main/java/io/quarkus/deployment/dev/testing/TestSupport.java
index a03138e2f7e3a..50fa7935ddc2a 100644
--- a/core/deployment/src/main/java/io/quarkus/deployment/dev/testing/TestSupport.java
+++ b/core/deployment/src/main/java/io/quarkus/deployment/dev/testing/TestSupport.java
@@ -17,7 +17,9 @@
 import java.util.Set;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.BiConsumer;
 import java.util.function.Consumer;
+import java.util.function.Predicate;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
@@ -322,6 +324,8 @@ public synchronized void stop() {
         for (var runner : moduleRunners) {
             runner.abort();
         }
+        TestWatchedFiles.setWatchedFilesListener(
+                (BiConsumer<Map<String, Boolean>, List<Map.Entry<Predicate<String>, Boolean>>>) null);
     }
 
     public void runTests() {
diff --git a/core/deployment/src/main/java/io/quarkus/deployment/proxy/ProxyFactory.java b/core/deployment/src/main/java/io/quarkus/deployment/proxy/ProxyFactory.java
index 7b379d7c1d5af..571c1fcb5232d 100644
--- a/core/deployment/src/main/java/io/quarkus/deployment/proxy/ProxyFactory.java
+++ b/core/deployment/src/main/java/io/quarkus/deployment/proxy/ProxyFactory.java
@@ -79,6 +79,10 @@ public ProxyFactory(ProxyConfiguration<T> configuration) {
         }
     }
 
+    public ClassLoader getClassLoader() {
+        return classLoader;
+    }
+
     private boolean findConstructor(Class<?> clazz, boolean allowPackagePrivate, boolean allowInject) {
         Constructor<?>[] ctors = clazz.getDeclaredConstructors();
         if (allowInject) {
diff --git a/core/deployment/src/main/java/io/quarkus/deployment/recording/RecordingProxyFactories.java b/core/deployment/src/main/java/io/quarkus/deployment/recording/RecordingProxyFactories.java
index 29f39a82f0c86..73f6c009a55a3 100644
--- a/core/deployment/src/main/java/io/quarkus/deployment/recording/RecordingProxyFactories.java
+++ b/core/deployment/src/main/java/io/quarkus/deployment/recording/RecordingProxyFactories.java
@@ -13,8 +13,9 @@ class RecordingProxyFactories {
     static <T> void put(Class<T> clazz, ProxyFactory<T> proxyFactory) {
         RECORDING_PROXY_FACTORIES.put(clazz, proxyFactory);
 
-        if (clazz.getClassLoader() instanceof QuarkusClassLoader) {
-            ((QuarkusClassLoader) clazz.getClassLoader()).addCloseTask(new Runnable() {
+        ClassLoader proxyClassLoader = proxyFactory.getClassLoader();
+        if (proxyClassLoader instanceof QuarkusClassLoader) {
+            ((QuarkusClassLoader) proxyClassLoader).addCloseTask(new Runnable() {
                 @Override
                 public void run() {
                     RecordingProxyFactories.RECORDING_PROXY_FACTORIES.remove(clazz);
diff --git a/core/deployment/src/main/java/io/quarkus/deployment/steps/ClassTransformingBuildStep.java b/core/deployment/src/main/java/io/quarkus/deployment/steps/ClassTransformingBuildStep.java
index a0f7c275eda8e..f9232542a3a8c 100644
--- a/core/deployment/src/main/java/io/quarkus/deployment/steps/ClassTransformingBuildStep.java
+++ b/core/deployment/src/main/java/io/quarkus/deployment/steps/ClassTransformingBuildStep.java
@@ -40,6 +40,7 @@
 import io.quarkus.deployment.builditem.ApplicationArchivesBuildItem;
 import io.quarkus.deployment.builditem.ArchiveRootBuildItem;
 import io.quarkus.deployment.builditem.BytecodeTransformerBuildItem;
+import io.quarkus.deployment.builditem.CuratedApplicationShutdownBuildItem;
 import io.quarkus.deployment.builditem.LaunchModeBuildItem;
 import io.quarkus.deployment.builditem.LiveReloadBuildItem;
 import io.quarkus.deployment.builditem.RemovedResourceBuildItem;
@@ -71,13 +72,19 @@ public static byte[] transform(String className, byte[] classData) {
         return lastTransformers.apply(className, classData);
     }
 
+    private static void reset() {
+        lastTransformers = null;
+        transformedClassesCache.clear();
+    }
+
     @BuildStep
     TransformedClassesBuildItem handleClassTransformation(List<BytecodeTransformerBuildItem> bytecodeTransformerBuildItems,
             ApplicationArchivesBuildItem appArchives, LiveReloadBuildItem liveReloadBuildItem,
             LaunchModeBuildItem launchModeBuildItem, ClassLoadingConfig classLoadingConfig,
             CurateOutcomeBuildItem curateOutcomeBuildItem, List<RemovedResourceBuildItem> removedResourceBuildItems,
             ArchiveRootBuildItem archiveRoot, LaunchModeBuildItem launchMode, PackageConfig packageConfig,
-            ExecutorService buildExecutor)
+            ExecutorService buildExecutor,
+            CuratedApplicationShutdownBuildItem shutdown)
             throws ExecutionException, InterruptedException {
         if (bytecodeTransformerBuildItems.isEmpty() && classLoadingConfig.removedResources.isEmpty()
                 && removedResourceBuildItems.isEmpty()) {
@@ -117,6 +124,7 @@ TransformedClassesBuildItem handleClassTransformation(List<BytecodeTransformerBu
         final ConcurrentLinkedDeque<Future<TransformedClassesBuildItem.TransformedClass>> transformed = new ConcurrentLinkedDeque<>();
         final Map<Path, Set<TransformedClassesBuildItem.TransformedClass>> transformedClassesByJar = new HashMap<>();
         ClassLoader transformCl = Thread.currentThread().getContextClassLoader();
+        shutdown.addCloseTask(ClassTransformingBuildStep::reset, true);
         lastTransformers = new BiFunction<String, byte[], byte[]>() {
             @Override
             public byte[] apply(String className, byte[] originalBytes) {
diff --git a/core/devmode-spi/src/main/java/io/quarkus/dev/testing/TestWatchedFiles.java b/core/devmode-spi/src/main/java/io/quarkus/dev/testing/TestWatchedFiles.java
index 2744d7f636778..134b26f1f333c 100644
--- a/core/devmode-spi/src/main/java/io/quarkus/dev/testing/TestWatchedFiles.java
+++ b/core/devmode-spi/src/main/java/io/quarkus/dev/testing/TestWatchedFiles.java
@@ -62,7 +62,7 @@ public synchronized static void setWatchedFilePaths(Map<String, Boolean> watched
     public synchronized static void setWatchedFilesListener(
             BiConsumer<Map<String, Boolean>, List<Entry<Predicate<String>, Boolean>>> watchedFilesListener) {
         TestWatchedFiles.watchedFilesListener = watchedFilesListener;
-        if (watchedFilePaths != null) {
+        if (watchedFilesListener != null && watchedFilePaths != null) {
             watchedFilesListener.accept(watchedFilePaths, watchedFilePredicates);
         }
     }
diff --git a/core/runtime/src/main/java/io/quarkus/runtime/dev/io/NioThreadPoolRecorder.java b/core/runtime/src/main/java/io/quarkus/runtime/dev/io/NioThreadPoolRecorder.java
index c14b2829d6731..0138b5bf85585 100644
--- a/core/runtime/src/main/java/io/quarkus/runtime/dev/io/NioThreadPoolRecorder.java
+++ b/core/runtime/src/main/java/io/quarkus/runtime/dev/io/NioThreadPoolRecorder.java
@@ -8,12 +8,17 @@
 public class NioThreadPoolRecorder {
 
     public void updateTccl(ShutdownContext context) {
-        ClassLoader old = NioThreadPoolThreadFactory.updateTccl(Thread.currentThread().getContextClassLoader());
-        context.addLastShutdownTask(new Runnable() {
-            @Override
-            public void run() {
-                NioThreadPoolThreadFactory.updateTccl(old);
-            }
-        });
+        ClassLoader newTccl = Thread.currentThread().getContextClassLoader();
+        ClassLoader oldTccl = NioThreadPoolThreadFactory.updateTccl(newTccl);
+        if (newTccl != oldTccl) {
+            context.addLastShutdownTask(new Runnable() {
+                @Override
+                public void run() {
+                    NioThreadPoolThreadFactory.updateTccl(oldTccl);
+                }
+            });
+        }
+        // Else: don't add an unnecessary shutdown task that may hold a reference to a QuarkusClassLoader,
+        // which could be a problem with QuarkusUnitTest since it creates one classloader per test.
     }
 }
diff --git a/extensions/vertx-http/deployment/src/main/java/io/quarkus/devui/deployment/menu/ConfigurationProcessor.java b/extensions/vertx-http/deployment/src/main/java/io/quarkus/devui/deployment/menu/ConfigurationProcessor.java
index 6818ff8fb5c38..2f2842e10d1b4 100644
--- a/extensions/vertx-http/deployment/src/main/java/io/quarkus/devui/deployment/menu/ConfigurationProcessor.java
+++ b/extensions/vertx-http/deployment/src/main/java/io/quarkus/devui/deployment/menu/ConfigurationProcessor.java
@@ -24,6 +24,7 @@
 import io.quarkus.deployment.annotations.ExecutionTime;
 import io.quarkus.deployment.annotations.Record;
 import io.quarkus.deployment.builditem.ConfigDescriptionBuildItem;
+import io.quarkus.deployment.builditem.CuratedApplicationShutdownBuildItem;
 import io.quarkus.deployment.builditem.DevServicesLauncherConfigResultBuildItem;
 import io.quarkus.dev.config.CurrentConfig;
 import io.quarkus.dev.console.DevConsoleManager;
@@ -95,7 +96,8 @@ void registerConfigs(List<ConfigDescriptionBuildItem> configDescriptionBuildItem
     void registerJsonRpcService(
             BuildProducer<JsonRPCProvidersBuildItem> jsonRPCProvidersProducer,
             BuildProducer<SyntheticBeanBuildItem> syntheticBeanProducer,
-            ConfigDevUIRecorder recorder) {
+            ConfigDevUIRecorder recorder,
+            CuratedApplicationShutdownBuildItem shutdown) {
 
         DevConsoleManager.register("config-update-property", map -> {
             Map<String, String> values = Collections.singletonMap(map.get("name"), map.get("value"));
@@ -116,6 +118,13 @@ void registerJsonRpcService(
                         .done());
 
         CurrentConfig.EDITOR = ConfigurationProcessor::updateConfig;
+        shutdown.addCloseTask(new Runnable() {
+            @Override
+            public void run() {
+                CurrentConfig.EDITOR = null;
+                CurrentConfig.CURRENT = Collections.emptyList();
+            }
+        }, true);
 
         jsonRPCProvidersProducer.produce(new JsonRPCProvidersBuildItem("devui-configuration", ConfigJsonRPCService.class));
     }
diff --git a/extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/runtime/VertxHttpRecorder.java b/extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/runtime/VertxHttpRecorder.java
index c6066e29c3890..6b14e7198c9f3 100644
--- a/extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/runtime/VertxHttpRecorder.java
+++ b/extensions/vertx-http/runtime/src/main/java/io/quarkus/vertx/http/runtime/VertxHttpRecorder.java
@@ -229,7 +229,7 @@ public static void shutDownDevMode() {
         }
         rootHandler = null;
         hotReplacementHandler = null;
-
+        hotReplacementContext = null;
     }
 
     public static void startServerAfterFailedStart() {
diff --git a/extensions/vertx/runtime/src/main/java/io/quarkus/vertx/core/runtime/VertxCoreRecorder.java b/extensions/vertx/runtime/src/main/java/io/quarkus/vertx/core/runtime/VertxCoreRecorder.java
index 5d578a4160c90..26e0cbb4ad1c9 100644
--- a/extensions/vertx/runtime/src/main/java/io/quarkus/vertx/core/runtime/VertxCoreRecorder.java
+++ b/extensions/vertx/runtime/src/main/java/io/quarkus/vertx/core/runtime/VertxCoreRecorder.java
@@ -423,6 +423,7 @@ public void handle(AsyncResult<Void> ar) {
                 Thread.currentThread().interrupt();
                 throw new IllegalStateException("Exception when closing Vert.x instance", e);
             }
+            LateBoundMDCProvider.setMDCProviderDelegate(null);
             vertx = null;
         }
     }
diff --git a/extensions/vertx/runtime/src/main/java/io/quarkus/vertx/runtime/VertxRecorder.java b/extensions/vertx/runtime/src/main/java/io/quarkus/vertx/runtime/VertxRecorder.java
index 12dbb305919cf..bd2e203ea3dd0 100644
--- a/extensions/vertx/runtime/src/main/java/io/quarkus/vertx/runtime/VertxRecorder.java
+++ b/extensions/vertx/runtime/src/main/java/io/quarkus/vertx/runtime/VertxRecorder.java
@@ -77,6 +77,7 @@ public static Vertx getVertx() {
 
     void destroy() {
         messageConsumers = null;
+        vertx = null;
     }
 
     void registerMessageConsumers(Map<String, ConsumeEvent> messageConsumerConfigurations) {