apache/dubbo · error · IllegalStateException

Found multiple <configType>s with unique service name [<uniq

Error message

Found multiple <configType>s with unique service name [<uniqueServiceName>], previous: <prevConfig>, later: <config>. There can only be one instance of <configType> with the same triple (group, interface, version). If multiple instances are required for the same interface, please use a different group or version.

What it means

Thrown by ModuleConfigManager.findDuplicatedInterfaceConfig() (when ignoreDuplicatedInterface is false) when a second ServiceConfigBase with the same unique service name (group+interface+version triple) is registered. The unique service name must be unique per service identity; a duplicate triple is ambiguous for registration and routing. When ignoreDuplicatedInterface is true it only warns instead.

Source

Thrown at dubbo-common/src/main/java/org/apache/dubbo/config/context/ModuleConfigManager.java:267

            if (prevConfig.equals(config)) {
                // Is there any problem with ignoring duplicate and equivalent but different ReferenceConfig instances?
                if (logger.isWarnEnabled() && duplicatedConfigs.add(config)) {
                    logger.warn(COMMON_UNEXPECTED_EXCEPTION, "", "", "Ignore duplicated and equal config: " + config);
                }
                return prevConfig;
            }

            String configType = config.getClass().getSimpleName();
            String msg = "Found multiple " + configType + "s with unique service name [" + uniqueServiceName
                    + "], previous: " + prevConfig + ", later: " + config + ". " + "There can only be one instance of "
                    + configType + " with the same triple (group, interface, version). "
                    + "If multiple instances are required for the same interface, please use a different group or version.";

            if (logger.isWarnEnabled() && duplicatedConfigs.add(config)) {
                logger.warn(COMMON_UNEXPECTED_EXCEPTION, "", "", msg);
            }
            if (!this.ignoreDuplicatedInterface) {
                throw new IllegalStateException(msg);
            }
        }
        return prevConfig;
    }

    private void removeInterfaceConfig(AbstractInterfaceConfig config) {
        String uniqueServiceName;
        Map<String, AbstractInterfaceConfig> configCache;
        if (config instanceof ReferenceConfigBase) {
            return;
        } else if (config instanceof ServiceConfigBase) {
            ServiceConfigBase serviceConfig = (ServiceConfigBase) config;
            uniqueServiceName = serviceConfig.getUniqueServiceName();
            configCache = serviceConfigCache;
        } else {
            throw new IllegalArgumentException(
                    "Illegal type of parameter 'config' : " + config.getClass().getName());
        }

View on GitHub (pinned to 3a3043227f)

Solutions

1. Differentiate the services by group or version so the (group, interface, version) triple is unique.
2. Remove the duplicate service export.
3. Set ignoreDuplicatedInterface=true (dubbo.config.ignore-duplicated-interface) only if the duplicate is intentional and equivalent.

Example fix

<!-- before: same triple -->
<dubbo:service interface="com.x.Foo" group="g" version="1.0"/>
<dubbo:service interface="com.x.Foo" group="g" version="1.0"/>
<!-- after: differ by version -->
<dubbo:service interface="com.x.Foo" group="g" version="1.0"/>
<dubbo:service interface="com.x.Foo" group="g" version="2.0"/>

// Ensure (group, interface, version) uniqueness before registering
String key = group + "/" + iface.getName() + ":" + version;
if (registeredServiceKeys.contains(key)) {
    throw new IllegalStateException("Duplicate service identity: " + key + "; change group or version");
}
registeredServiceKeys.add(key);
serviceConfig.export();

static boolean isUniqueServiceTriple(java.util.Set<String> seen, String group, String iface, String version) {
    return seen.add(group + "/" + iface + ":" + version);
}

try {
    serviceConfig.export();
} catch (IllegalStateException e) {
    if (e.getMessage().contains("Found multiple") && e.getMessage().contains("unique service name")) {
        serviceConfig.setVersion(serviceConfig.getVersion() + "-alt"); // disambiguate
        serviceConfig.export();
    } else throw e;
}

When it happens

Trigger: Registering two ServiceConfig with the same interface, group, and version. Programmatic double-registration of the same service identity. Two Spring beans exporting the same interface without differing group/version.

Common situations: Accidentally defining the same <dubbo:service interface=...> in two contexts. Merging modules that both export the same interface. Forgetting to set group/version to disambiguate multi-implementation exports.

Related errors

• Expected single instance of <configType>, but found <size> i
• Found more than one config by name: <name>, instances: <list
• Duplicate Configs found for <configName>, only one unique <c
• Illegal type of parameter 'config' : <config.getClass().getN
• Invalid configurator rule, please specify at least one param

AI-assisted analysis of apache/dubbo@3a3043227f (2026-08-14). Data as JSON: /api/errors/be9583ac9fd13cd6. Report an issue: GitHub.