spring-projects/spring-security · error · BeanDefinitionStoreException

No id supplied and another bean is already registered as {Be

Error message

No id supplied and another bean is already registered as {BeanIds.USER_DETAILS_SERVICE}

What it means

The <user-service> / user details XML parser resolves a bean id for the UserDetailsService. When no explicit 'id' attribute is supplied and the element is top-level, the parser defaults to the reserved id 'userDetailsService' (BeanIds.USER_DETAILS_SERVICE); if a bean with that id is already registered, it throws BeanDefinitionStoreException to prevent a silent overwrite.

Source

Thrown at config/src/main/java/org/springframework/security/config/authentication/AbstractUserDetailsServiceBeanDefinitionParser.java:89

	private String resolveId(Element element, AbstractBeanDefinition definition, ParserContext pc)
			throws BeanDefinitionStoreException {
		String id = element.getAttribute("id");
		if (pc.isNested()) {
			// We're inside an <authentication-provider> element
			if (!StringUtils.hasText(id)) {
				id = pc.getReaderContext().generateBeanName(definition);
			}
			ValueHolder userDetailsServiceValueHolder = new ValueHolder(new RuntimeBeanReference(id));
			userDetailsServiceValueHolder.setName("userDetailsService");
			BeanDefinition container = pc.getContainingBeanDefinition();
			container.getConstructorArgumentValues().addGenericArgumentValue(userDetailsServiceValueHolder);
		}
		if (StringUtils.hasText(id)) {
			return id;
		}
		// If top level, use the default name or throw an exception if already used
		if (pc.getRegistry().containsBeanDefinition(BeanIds.USER_DETAILS_SERVICE)) {
			throw new BeanDefinitionStoreException(
					"No id supplied and another bean is already registered as " + BeanIds.USER_DETAILS_SERVICE);
		}
		return BeanIds.USER_DETAILS_SERVICE;
	}

}

View on GitHub (pinned to 96852e8860)

Solutions

1. Give each <user-service> element a unique id attribute, e.g. <user-service id="adminUsers"> and <user-service id="appUsers">.
2. Remove the duplicate top-level user-service element if only one is needed.
3. If two UserDetailServices must both be used, wrap them in a delegating implementation and register that as the single userDetailsService bean.
4. Reference the intended service explicitly with user-service-ref on <authentication-provider> instead of relying on the default id.

Example fix

<!-- before -->
<user-service>
  <user name="admin" password="{noop}pass" authorities="ROLE_ADMIN"/>
</user-service>
<user-service>
  <user name="user" password="{noop}pass" authorities="ROLE_USER"/>
</user-service>
<!-- after -->
<user-service id="adminUserService">
  <user name="admin" password="{noop}pass" authorities="ROLE_ADMIN"/>
</user-service>
<user-service id="appUserService">
  <user name="user" password="{noop}pass" authorities="ROLE_USER"/>
</user-service>

// Before parsing, verify no duplicate top-level user-service elements and no id collision
boolean hasUniqueId(List<Element> userServices) {
    Set<String> ids = new HashSet<>();
    for (Element el : userServices) {
        String id = el.getAttribute("id");
        if (!ids.add(id.isEmpty() ? "userDetailsService" : id)) return false;
    }
    return true;
}

try {
    context = new ClassPathXmlApplicationContext("security.xml");
} catch (BeanDefinitionStoreException e) {
    if (e.getMessage() != null && e.getMessage().contains("USER_DETAILS_SERVICE")) {
        throw new IllegalStateException("Give each <user-service> a unique id attribute", e);
    }
    throw e;
}

When it happens

Trigger: Declaring two or more top-level <user-service> (or <jdbc-user-service>, <ldap-user-service>) elements in Spring Security XML namespace config without giving each an 'id' attribute; or a bean named 'userDetailsService' already exists when a top-level user-service element is parsed.

Common situations: Legacy XML configs with multiple in-memory user stores (e.g. after a merge of config files); copy-pasting a <user-service> block without an id; combining an explicit UserDetailsService @Bean with XML user-service elements.

Understand the failure class

Background: "already exists" / EEXIST / FileAlreadyExistsException: what the 'file already exists' error means and how to fix it — this error's family across 37 libraries.

Related errors

• Use of a properties file and user elements are mutually excl
• You must supply user definitions, either with <user> child e
• Did you forget to add a global <authentication-manager> elem
• Unknown channel attribute {requiredChannel}
• Could not create CorsFilter

AI-assisted analysis of spring-projects/spring-security@96852e8860 (2026-09-10). Data as JSON: /api/errors/d134c031aec6ecee. Report an issue: GitHub.