hibernate/hibernate-orm · error · IllegalArgumentException

Fetch was already defined for %s.%s : %s

Error message

Fetch was already defined for %s.%s : %s

What it means

Error "Fetch was already defined for %s.%s : %s" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/query/results/internal/dynamic/AbstractFetchBuilderContainer.java:67

		return (T) this;
	}

	@Override
	public T addProperty(Fetchable fetchable, String... columnAliases) {
		final var fetchBuilder = addProperty( fetchable );
		ArrayHelper.forEach( columnAliases, fetchBuilder::addColumnAlias );
		return (T) this;
	}

	@Override
	public DynamicFetchBuilder addProperty(Fetchable fetchable) {
		if ( fetchBuilderMap == null ) {
			fetchBuilderMap = new HashMap<>();
		}
		else {
			final var existing = fetchBuilderMap.get( fetchable );
			if ( existing != null ) {
				throw new IllegalArgumentException(
						String.format(
								Locale.ROOT,
								"Fetch was already defined for %s.%s : %s",
								getPropertyBase(),
								fetchable,
								existing
						)
				);
			}
		}

		final var fetchBuilder = new DynamicFetchBuilderStandard( fetchable	);
		fetchBuilderMap.put( fetchable, fetchBuilder );
		return fetchBuilder;
	}

	@Override
	public void addFetchBuilder(Fetchable fetchable, FetchBuilder fetchBuilder) {

View on GitHub (pinned to fad1729dce)

Solutions

1. A fetch for that attribute was already defined. Remove the duplicate fetch definition.

When it happens

Trigger: A dynamic native-result mapping is built inconsistently: Fetch was already defined for <value>.<value> : <value>

Common situations: Defining the same fetch twice, fetching an unsupported type, or an instantiation mapping with no constructor arguments.

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/9eb17e4cb3dfafc8. Report an issue: GitHub.