oracle/graal · error · IllegalStateException

No singleton found for ${registration}

Error message

No singleton found for ${registration}

What it means

The singleton deserializer resolves a CompilerInterfaceDeclarations.Registration to a live singleton by asking the CompilationProxies.ProxyFactory for a proxy. If the factory returns null, no singleton instance was ever registered for that name under the current compiler interface declarations, so replay cannot bind the recorded object back to a real component.

Source

Thrown at compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hotspot/replaycomp/JsonReplayCodec.java:269

            return registration.clazz();
        }

        @Override
        public String tag() {
            return clazz().getName();
        }

        @Override
        public void serialize(Object instance, JsonBuilder.ObjectBuilder objectBuilder, RecursiveSerializer serializer) {
        }

        @Override
        public Object deserialize(EconomicMap<String, Object> json, RecursiveDeserializer deserializer, CompilationProxies.ProxyFactory proxyFactory) {
            if (singletonProxy == null) {
                singletonProxy = proxyFactory.createProxy(registration);
            }
            if (singletonProxy == null) {
                throw new IllegalStateException("No singleton found for " + registration);
            }
            return singletonProxy;
        }
    }

    private static final class RegisteredInstanceSerializer implements ObjectSerializer {
        private final CompilerInterfaceDeclarations.Registration registration;

        private final EconomicMap<Object, Integer> instanceId;

        private final EconomicMap<Integer, Object> proxyById;

        private RegisteredInstanceSerializer(CompilerInterfaceDeclarations.Registration registration) {
            this.registration = registration;
            this.instanceId = EconomicMap.create();
            this.proxyById = EconomicMap.create();
            if (registration.singleton()) {
                throw new IllegalArgumentException();

View on GitHub (pinned to a66e9ccd1d)

Solutions

1. Record and replay with the exact same GraalVM/JVMCI build so registrations match
2. Inspect the registration name in the JSON file and grep CompilerInterfaceDeclarations for it to see whether it exists in your build
3. If the component was renamed, patch the JSON's singleton tag or add a compatibility alias registration
4. Ensure the same compiler configuration flags (e.g. GC selection, hosted vs JIT mode) are used on both sides

// Verify the registration exists before deserialization
if (!CompilerInterfaceDeclarations.get(registrationName).isPresent()) {
    throw new IllegalStateException("Replay file references unknown singleton: " + registrationName);
}

When it happens

Trigger: Deserializing a JSON replay file whose 'singleton' tag names a registration that does not exist in the replaying JVM's CompilerInterfaceDeclarations — e.g. a backend/phase singleton that was renamed, removed, or is only registered in a different configuration (different GC, JVMCI version, or community/enterprise build).

Common situations: Replaying a file recorded on a different GraalVM version where the singleton name differs; replaying with a different compiler configuration that skips registering the component; typos or renamed registrations after refactors.

Related errors

• Unknown replay singleton kind
• Unknown class ${className} for constant${value}
• Invalid marker type.
• Invalid constant.
• Unexpected value: ${name}

AI-assisted analysis of oracle/graal@a66e9ccd1d (2026-08-14). Data as JSON: /api/errors/576ffdc6acc4fee7. Report an issue: GitHub.