Wrap the managed worker thread pool to disallow shutdown by applicati…

…on/other extensions

core/runtime/src/main/java/io/quarkus/runtime/ExecutorRecorder.java

@@ -17,6 +17,7 @@
 import org.wildfly.common.cpu.ProcessorInfo;
 
 import io.quarkus.runtime.annotations.Recorder;
+import io.quarkus.runtime.util.ManagedScheduledExecutorService;
 
 /**
  *
@@ -57,8 +58,13 @@ public void run() {
         if (threadPoolConfig.prefill) {
             underlying.prestartAllCoreThreads();
         }
-        current = underlying;
-        return underlying;
+        ScheduledExecutorService managed = underlying;
+        // In prod mode we don't want to allow the executor to be shut down by the application or other extensions
+        if (launchMode == LaunchMode.NORMAL) {
+            managed = new ManagedScheduledExecutorService(underlying);
+        }
+        current = managed;
+        return managed;
     }
 
     private static Runnable createShutdownTask(ThreadPoolConfig threadPoolConfig, EnhancedQueueExecutor executor) {

core/runtime/src/main/java/io/quarkus/runtime/util/ForwardingScheduledExecutorService.java

@@ -0,0 +1,37 @@
+package io.quarkus.runtime.util;
+
+import java.util.concurrent.Callable;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Forwards all method calls to the scheduled executor service returned from the {@link #delegate()} method. Only non-default
+ * methods
+ * declared on the {@link ScheduledExecutorService} interface are forwarded.
+ */
+public abstract class ForwardingScheduledExecutorService extends ForwardingExecutorService implements ScheduledExecutorService {
+
+    protected abstract ScheduledExecutorService delegate();
+
+    @Override
+    public ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit) {
+        return delegate().schedule(command, delay, unit);
+    }
+
+    @Override
+    public <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit) {
+        return delegate().schedule(callable, delay, unit);
+    }
+
+    @Override
+    public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) {
+        return delegate().scheduleAtFixedRate(command, initialDelay, period, unit);
+    }
+
+    @Override
+    public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit) {
+        return delegate().scheduleWithFixedDelay(command, initialDelay, delay, unit);
+    }
+
+}

core/runtime/src/main/java/io/quarkus/runtime/util/ManagedScheduledExecutorService.java

@@ -0,0 +1,50 @@
+package io.quarkus.runtime.util;
+
+import java.util.List;
+import java.util.concurrent.ScheduledExecutorService;
+
+import org.jboss.logging.Logger;
+
+/**
+ * Forwards all method calls to the scheduled executor service returned from the {@link #delegate()} method.
+ * Does not allow shutdown
+ */
+public class ManagedScheduledExecutorService extends ForwardingScheduledExecutorService {
+
+    private static final Logger LOG = Logger.getLogger(ManagedScheduledExecutorService.class);
+
+    private final ScheduledExecutorService delegate;
+
+    public ManagedScheduledExecutorService(final ScheduledExecutorService delegate) {
+        this.delegate = delegate;
+    }
+
+    @Override
+    protected ScheduledExecutorService delegate() {
+        return delegate;
+    }
+
+    @Override
+    public boolean isShutdown() {
+        // managed executors are never shut down from the application's perspective
+        return false;
+    }
+
+    @Override
+    public boolean isTerminated() {
+        // managed executors are never shut down from the application's perspective
+        return false;
+    }
+
+    @Override
+    public void shutdown() {
+        LOG.debug("shutdown() not allowed on managed executor service");
+    }
+
+    @Override
+    public List<Runnable> shutdownNow() {
+        LOG.debug("shutdownNow() not allowed on managed executor service");
+        return List.of();
+    }
+
+}