spring-projects/spring-framework · error · IllegalArgumentException

Unable to locate method [{methodName}] on bean [{targetBeanN

Error message

Unable to locate method [{methodName}] on bean [{targetBeanName}]

What it means

Once the bean's class is known, MethodLocatingFactoryBean resolves the method via BeanUtils.resolveSignature(methodName, beanClass) (line 75). If resolveSignature returns null - i.e. no method of that name/signature exists on the class - Spring throws this IllegalArgumentException naming both the method and the bean.

Source

Thrown at spring-aop/src/main/java/org/springframework/aop/config/MethodLocatingFactoryBean.java:78

	}

	@Override
	public void setBeanFactory(BeanFactory beanFactory) {
		if (!StringUtils.hasText(this.targetBeanName)) {
			throw new IllegalArgumentException("Property 'targetBeanName' is required");
		}
		if (!StringUtils.hasText(this.methodName)) {
			throw new IllegalArgumentException("Property 'methodName' is required");
		}

		Class<?> beanClass = beanFactory.getType(this.targetBeanName);
		if (beanClass == null) {
			throw new IllegalArgumentException("Can't determine type of bean with name '" + this.targetBeanName + "'");
		}
		this.method = BeanUtils.resolveSignature(this.methodName, beanClass);

		if (this.method == null) {
			throw new IllegalArgumentException("Unable to locate method [" + this.methodName +
					"] on bean [" + this.targetBeanName + "]");
		}
	}


	@Override
	public @Nullable Method getObject() throws Exception {
		return this.method;
	}

	@Override
	public Class<Method> getObjectType() {
		return Method.class;
	}

	@Override
	public boolean isSingleton() {
		return true;

View on GitHub (pinned to 69bf83ad71)

Solutions

1. Open the target bean's class and confirm a method with the exact name exists and is public/non-private
2. For overloaded methods, supply a typed signature like "doWork(int,String)" (resolveSignature supports it) instead of just "doWork"
3. If the bean is proxied/scoped, make sure the method is declared on the interface or class that getType returns

Example fix

// before
<property name="methodName" value="doWork"/>  <!-- method renamed to execute -->

// after
<property name="methodName" value="execute"/>

// Resolve eagerly to fail with a clearer message:
Class<?> c = beanFactory.getType(targetBeanName);
Method m = BeanUtils.resolveSignature(methodName, c);
if (m == null) throw new IllegalStateException("No method " + methodName + " on " + c);

private static boolean methodExists(Class<?> type, String signature) {
  return type != null && BeanUtils.resolveSignature(signature, type) != null;
}

When it happens

Trigger: methodName does not match any method on the target bean's class; the method exists only on a superclass that ClassUtils cannot reach; the method was renamed/removed in a refactor; using a signature string with wrong parameter types.

Common situations: Refactor that renamed or deleted the target method while leaving the config stale; method is private and not resolvable; typo in method name; the bean's actual runtime class differs from the expected one (e.g. scoped-proxy or AOP-proxied bean whose getType returns the interface).

Related errors

• Property 'targetBeanName' is required
• Property 'methodName' is required
• Can't determine type of bean with name '{targetBeanName}'
• Property 'target' is required
• 'target' needs to be a bean reference, not a bean name as va

AI-assisted analysis of spring-projects/spring-framework@69bf83ad71 (2026-08-09). Data as JSON: /api/errors/fd5094d7d2dd0e0f. Report an issue: GitHub.