aeron-io/aeron · error · AeronException

registration id is not a Publication

Error message

registration id is not a Publication: ${resource.getClass().getSimpleName()}

What it means

Thrown by Aeron's ClientConductor.removePublication when the supplied registration id maps to a resource that exists but is not a Publication (e.g. a Subscription or Counter). The conductor tracks all client resources by registration id, and this cast-guard prevents releasing the wrong resource type.

Solutions

Pass the registration id returned by addPublication/addExclusivePublication only.
Check the resource type at the call site; use removeSubscription or removeCounter for other resources.
Fix id bookkeeping (name variables by resource type) so ids cannot be confused.

Example fix

// before
long id = client.addSubscription(channel, streamId).registrationId();
client.removePublication(id); // AeronException
// after
long pubId = client.addPublication(channel, streamId).registrationId();
client.removePublication(pubId);

Defensive patterns

Strategy: try-catch

Validate before calling

// track ids with the resource that produced them
if (!(resource instanceof Publication)) throw new IllegalStateException("id is not a publication");
client.removePublication(publication.registrationId());

Type guard

boolean isPublicationRegId(long regId) { return conductorResourceFor(regId) instanceof Publication; } // maintain your own registry map

Try / catch

try { client.removePublication(regId); } catch (AeronException e) { log.warn("reg id {} is not a Publication: {}", regId, e.getMessage()); }

Prevention

Store registration ids in typed wrappers per resource kind.
Always take the id from the same object you are releasing.
Avoid reusing generic long variables across add/remove calls.

When it happens

Trigger: Calling aeronClient.removePublication(registrationId) with an id that was returned from addSubscription, addCounter, or another non-publication registration.

Common situations: Mixing up registration ids stored in a map/registry; swapping ids after refactoring; reusing a variable holding a subscription id in a release call.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

AI-assisted analysis of aeron-io/aeron@6d60124e15 (2026-09-12). Data as JSON: /api/errors/70fe95c20c148b92. Report an issue: GitHub.

Appendix: source

Thrown at aeron-client/src/main/java/io/aeron/ClientConductor.java:695

        }
    }

    void removePublication(final long publicationRegistrationId)
    {
        clientLock.lock();
        try
        {
            if (NULL_VALUE == publicationRegistrationId || isTerminating || isClosed)
            {
                return;
            }

            ensureNotReentrant();

            final Object resource = resourceByRegIdMap.get(publicationRegistrationId);
            if (null != resource && !(resource instanceof Publication))
            {
                throw new AeronException("registration id is not a Publication: " +
                    resource.getClass().getSimpleName());
            }

            final Publication publication = (Publication)resource;
            boolean revokeOnClose = false;
            if (null != publication)
            {
                resourceByRegIdMap.remove(publicationRegistrationId);
                publication.internalClose();
                releaseLogBuffers(
                    publication.logBuffers(), publication.originalRegistrationId(), EXPLICIT_CLOSE_LINGER_NS);
                revokeOnClose = publication.revokeOnClose;
            }

            if (asyncCommandIdSet.remove(publicationRegistrationId) || null != publication)
            {
                asyncCommandIdSet.add(
                    driverProxy.removePublication(publicationRegistrationId, revokeOnClose));

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