Use custom thread factory for NIO

core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedDevModeMain.java

@@ -364,6 +364,9 @@ public void close() {
     //the main entry point, but loaded inside the augmentation class loader
     @Override
     public void accept(CuratedApplication o, Map<String, Object> params) {
+        //setup the dev mode thread pool for NIO
+        System.setProperty("java.nio.channels.DefaultThreadPool.threadFactory",
+                "io.quarkus.dev.io.NioThreadPoolThreadFactory");
         Timing.staticInitStarted(o.getBaseRuntimeClassLoader(), false);
         //https://github.com/quarkusio/quarkus/issues/9748
         //if you have an app with all daemon threads then the app thread

core/deployment/src/main/java/io/quarkus/deployment/dev/IsolatedTestModeMain.java

@@ -103,6 +103,8 @@ public void close() {
     //the main entry point, but loaded inside the augmentation class loader
     @Override
     public void accept(CuratedApplication o, Map<String, Object> params) {
+        System.setProperty("java.nio.channels.DefaultThreadPool.threadFactory",
+                "io.quarkus.dev.io.NioThreadPoolThreadFactory");
         Timing.staticInitStarted(o.getBaseRuntimeClassLoader(), false);
         try {
             curatedApplication = o;

core/deployment/src/main/java/io/quarkus/deployment/dev/io/NioThreadPoolDevModeProcessor.java

@@ -0,0 +1,21 @@
+package io.quarkus.deployment.dev.io;
+
+import io.quarkus.deployment.IsNormal;
+import io.quarkus.deployment.annotations.BuildStep;
+import io.quarkus.deployment.annotations.ExecutionTime;
+import io.quarkus.deployment.annotations.Produce;
+import io.quarkus.deployment.annotations.Record;
+import io.quarkus.deployment.builditem.ShutdownContextBuildItem;
+import io.quarkus.deployment.dev.testing.TestSetupBuildItem;
+import io.quarkus.runtime.dev.io.NioThreadPoolRecorder;
+
+public class NioThreadPoolDevModeProcessor {
+
+    @Produce(TestSetupBuildItem.class)
+    @BuildStep(onlyIfNot = IsNormal.class)
+    @Record(ExecutionTime.STATIC_INIT)
+    void setupTCCL(NioThreadPoolRecorder recorder, ShutdownContextBuildItem shutdownContextBuildItem) {
+        recorder.updateTccl(shutdownContextBuildItem);
+    }
+
+}

core/devmode-spi/src/main/java/io/quarkus/dev/io/NioThreadPoolThreadFactory.java

@@ -0,0 +1,45 @@
+package io.quarkus.dev.io;
+
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * We need to be able to update the TCCL of the NIO default thread pool in dev/test mode
+ * <p>
+ * This class lets us to that.
+ */
+public class NioThreadPoolThreadFactory implements ThreadFactory {
+
+    private static final CopyOnWriteArrayList<Thread> allThreads = new CopyOnWriteArrayList<>();
+    private static volatile ClassLoader currentCl = Thread.currentThread().getContextClassLoader();
+
+    @Override
+    public Thread newThread(Runnable r) {
+        AtomicReference<Thread> t = new AtomicReference<>();
+        Thread thread = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                try {
+                    r.run();
+                } finally {
+                    allThreads.remove(t.get());
+                }
+            }
+        }, "NIO IO Thread (created by Quarkus)");
+        t.set(thread);
+        thread.setDaemon(true);
+        allThreads.add(thread);
+        thread.setContextClassLoader(currentCl);
+        return thread;
+    }
+
+    public static ClassLoader updateTccl(ClassLoader cl) {
+        ClassLoader old = currentCl;
+        currentCl = cl;
+        for (Thread i : allThreads) {
+            i.setContextClassLoader(cl);
+        }
+        return old;
+    }
+}

core/runtime/src/main/java/io/quarkus/runtime/dev/io/NioThreadPoolRecorder.java

@@ -0,0 +1,19 @@
+package io.quarkus.runtime.dev.io;
+
+import io.quarkus.dev.io.NioThreadPoolThreadFactory;
+import io.quarkus.runtime.ShutdownContext;
+import io.quarkus.runtime.annotations.Recorder;
+
+@Recorder
+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);
+            }
+        });
+    }
+}