quarkusio/quarkus · error · UnsupportedOperationException

shutdownNow not allowed on managed executor service

Error message

shutdownNow not allowed on managed executor service

What it means

Same lifecycle restriction as shutdown(): DelegatingExecutorService.shutdownNow() throws UnsupportedOperationException because the wrapped executor is Quarkus-managed and must not be forcibly terminated by application code. Additionally note shutdownNow's return value (pending tasks) can never be provided for a managed pool.

Source

Thrown at extensions/virtual-threads/runtime/src/main/java/io/quarkus/virtual/threads/DelegatingExecutorService.java:43

        // container managed executors are never shut down from the application's perspective
        return false;
    }

    public boolean isTerminated() {
        // container managed executors are never shut down from the application's perspective
        return false;
    }

    public boolean awaitTermination(final long timeout, final TimeUnit unit) {
        return false;
    }

    public void shutdown() {
        throw new UnsupportedOperationException("shutdown not allowed on managed executor service");
    }

    public List<Runnable> shutdownNow() {
        throw new UnsupportedOperationException("shutdownNow not allowed on managed executor service");
    }

    public String toString() {
        return delegate.toString();
    }
}

View on GitHub (pinned to e1c734241f)

Solutions

1. Drop the shutdownNow() call; let Quarkus manage executor termination
2. Use an application-created executor for components that need to force shutdown
3. Use a completion flag/Future.cancel(true) per task instead of shutting down the whole pool

Example fix

// before
List<Runnable> pending = executor.shutdownNow();
// after
future.cancel(true); // cancel individual tasks instead

if (isQuarkusManaged(executor)) { /* never call shutdownNow */ }

boolean isManagedExecutor(ExecutorService es) { return es.getClass().getName().startsWith("io.quarkus.virtual.threads"); }

try { executor.shutdownNow(); } catch (UnsupportedOperationException ignored) { /* managed by Quarkus */ }

When it happens

Trigger: Calling shutdownNow() on the injected managed/virtual-thread executor service, typically during app shutdown or task cancellation logic.

Common situations: Code that cancels in-flight work at shutdown; third-party libraries that call shutdownNow() on an ExecutorService handed to them.

Related errors

• shutdown not allowed on managed executor service
• Trying to invoke ContextPropagation on a partially-configure
• This executor is managed by the container and cannot be shut
• Can only sync state on the server side of remote dev mode
• All parameters have already been loaded, it is too late to c

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/1c05a36a1fc2c2b1. Report an issue: GitHub.