spring-projects/spring-framework · error · IllegalArgumentException

Returning name '{}' is neither a valid argument name nor the

Error message

Returning name '{}' is neither a valid argument name nor the fully-qualified name of a Java type on the classpath. Root cause: {}

What it means

Thrown by setReturningNameNoCheck (line 299-315) when the returning value is not a Java variable name AND ClassUtils.forName cannot load it as a type on the aspect's classloader. Spring treats a non-identifier returning value as a fully-qualified type used to narrow the matched return type; if it is neither a name nor a loadable type, binding is impossible.

Source

Thrown at spring-aop/src/main/java/org/springframework/aop/aspectj/AbstractAspectJAdvice.java:310

		throw new UnsupportedOperationException("Only afterReturning advice can be used to bind a return value");
	}

	/**
	 * We need to hold the returning name at this level for argument binding calculations,
	 * this method allows the afterReturning advice subclass to set the name.
	 */
	protected void setReturningNameNoCheck(String name) {
		// name could be a variable or a type...
		if (isVariableName(name)) {
			this.returningName = name;
		}
		else {
			// assume a type
			try {
				this.discoveredReturningType = ClassUtils.forName(name, getAspectClassLoader());
			}
			catch (Throwable ex) {
				throw new IllegalArgumentException("Returning name '" + name +
						"' is neither a valid argument name nor the fully-qualified " +
						"name of a Java type on the classpath. Root cause: " + ex);
			}
		}
	}

	protected Class<?> getDiscoveredReturningType() {
		return this.discoveredReturningType;
	}

	protected @Nullable Type getDiscoveredReturningGenericType() {
		return this.discoveredReturningGenericType;
	}

	public void setThrowingName(String name) {
		throw new UnsupportedOperationException("Only afterThrowing advice can be used to bind a thrown exception");
	}

View on GitHub (pinned to e8729d0438)

Solutions

1. If returning should bind a parameter, use the exact advice parameter name (a valid Java identifier).
2. If returning is meant to narrow by type, supply the fully-qualified type name and verify it is on the classpath.
3. Fix typos and package names; ensure the containing jar is a dependency.
4. Remove the returning attribute if no return binding/narrowing is intended.

Example fix

// before
<aop:after-returning method="log" returning="Reesult" pointcut="..."/>
// after
<aop:after-returning method="log" returning="result" pointcut="..."/>

// Validate a returning value before setting it: must be an identifier or a loadable type.
String name = returningValue.strip();
boolean ok = AspectJProxyUtils.isVariableName(name);
if (!ok) {
    try { ClassUtils.forName(name, aspectClassLoader); ok = true; }
    catch (Throwable t) { ok = false; }
}
if (!ok) throw new IllegalArgumentException("Invalid returning value: " + name);

try {
    ((AspectJAfterReturningAdvice) advice).setReturningName(name);
} catch (IllegalArgumentException ex) {
    throw new IllegalArgumentException(
        "'returning' must be a parameter name or fully-qualified type on the classpath: " + name, ex);
}

When it happens

Trigger: Setting 'returning' to a string that is neither a valid Java identifier (e.g. '123', 'a.b.c' where c isn't a class) nor a fully-qualified class name resolvable by the aspect ClassLoader (typo, missing dependency, wrong package).

Common situations: Typo in the returning attribute; specifying a simple class name instead of fully-qualified; the return-narrowing type lives in a jar not on the classpath; refactoring that renamed/moved the return type without updating the aspect XML/annotation.

Related errors

• Throwing name '{}' is neither a valid argument name nor the
• Returning argument name '{}' was not bound in advice argumen
• 'argumentNames' property of AbstractAspectJAdvice contains a
• Only afterReturning advice can be used to bind a return valu
• Advice method [{}] requires {} arguments to be bound by name

AI-assisted analysis of spring-projects/spring-framework@e8729d0438 (2026-08-04). Data as JSON: /data/errors/6f7f3b717a0002f9.json. Report an issue: GitHub.