spring-projects/spring-framework · error · IllegalArgumentException

'sourceList' is required

Error message

'sourceList' is required

What it means

Error "'sourceList' is required" thrown in spring-projects/spring-framework.

Source

Thrown at spring-beans/src/main/java/org/springframework/beans/factory/config/ListFactoryBean.java:80

		}
		if (!List.class.isAssignableFrom(targetListClass)) {
			throw new IllegalArgumentException("'targetListClass' must implement [java.util.List]");
		}
		this.targetListClass = targetListClass;
	}


	@Override
	@SuppressWarnings("rawtypes")
	public Class<List> getObjectType() {
		return List.class;
	}

	@Override
	@SuppressWarnings("unchecked")
	protected List<Object> createInstance() {
		if (this.sourceList == null) {
			throw new IllegalArgumentException("'sourceList' is required");
		}
		List<Object> result = null;
		if (this.targetListClass != null) {
			result = BeanUtils.instantiateClass(this.targetListClass);
		}
		else {
			result = new ArrayList<>(this.sourceList.size());
		}
		Class<?> valueType = null;
		if (this.targetListClass != null) {
			valueType = ResolvableType.forClass(this.targetListClass).asCollection().resolveGeneric();
		}
		if (valueType != null) {
			TypeConverter converter = getBeanTypeConverter();
			for (Object elem : this.sourceList) {
				result.add(converter.convertIfNecessary(elem, valueType));
			}
		}

View on GitHub (pinned to e8729d0438)

When it happens

Trigger: Thrown at spring-beans/src/main/java/org/springframework/beans/factory/config/ListFactoryBean.java:80 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of spring-projects/spring-framework@e8729d0438 (2026-08-04). Data as JSON: /data/errors/60efb09b3ca52a1c.json. Report an issue: GitHub.