hibernate/hibernate-orm · error · UnsupportedOperationException

null entity instance

Error message

null entity instance

What it means

Error "null entity instance" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/loader/ast/internal/SingleIdEntityLoaderProvidedQueryImpl.java:60

	@Override @SuppressWarnings("unchecked")
	public T load(Object pkValue, LockOptions lockOptions, Boolean readOnly, SharedSessionContractImplementor session) {
		final var mappedJavaType = (JavaType<T>) entityDescriptor.getMappedJavaType();
		final var query = namedQueryMemento.toSelectionQuery( session, mappedJavaType.getJavaTypeClass() );
		query.setParameter( (Parameter<Object>) query.getParameters().iterator().next(), pkValue );
		query.setQueryFlushMode( QueryFlushMode.NO_FLUSH );
		query.setResultListTransformer( uniqueResultTransformer() );
		return query.uniqueResult();
	}

	@Override
	public T load(
			Object pkValue,
			Object entityInstance,
			LockOptions lockOptions,
			Boolean readOnly,
			SharedSessionContractImplementor session) {
		if ( entityInstance != null ) {
			throw new UnsupportedOperationException("null entity instance");
		}
		return load( pkValue, lockOptions, readOnly, session );
	}

	@Override
	public Object[] loadDatabaseSnapshot(Object id, SharedSessionContractImplementor session) {
		return EMPTY_OBJECT_ARRAY;
	}
}

View on GitHub (pinned to fad1729dce)

Solutions

1. Internal loader invariant violated; ensure the provided query for the entity returns a result and the entity mapping is valid.

When it happens

Trigger: Thrown at hibernate-core/src/main/java/org/hibernate/loader/ast/internal/SingleIdEntityLoaderProvidedQueryImpl.java:60 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/93fd3ecfef62e4fc. Report an issue: GitHub.