hibernate/hibernate-orm · error · TransformationException

Error transforming many-to-any :

Error message

Error transforming many-to-any : 

What it means

Thrown by HbmXmlTransformer when transformPluralAny fails for a collection declared with <many-to-any/>. In current Hibernate this catch is effectively always hit together with error 365: transferPluralAny unconditionally throws UnsupportedOperationException('Not yet implemented'), which this TransformationException then wraps along with the mapping Origin.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/boot/jaxb/hbm/transform/HbmXmlTransformer.java:2239

				else if ( hbmCollection.getManyToMany() != null ) {
					try {
						if ( hbmCollection.getManyToMany().isUnique() ) {
							attributes.getOneToManyAttributes().add( transformManyToManyToOneToMany( hbmCollection, propertyInfo ) );
						}
						else {
							attributes.getManyToManyAttributes().add( transformManyToMany( hbmCollection, propertyInfo ) );
						}
					}
					catch (Exception e) {
						throw new TransformationException( "Error transforming many-to-many : " + hbmCollection.getName(), e, origin() );
					}
				}
				else if ( hbmCollection.getManyToAny() != null ) {
					try {
						attributes.getPluralAnyMappingAttributes().add( transformPluralAny( hbmCollection ) );
					}
					catch (Exception e) {
						throw new TransformationException( "Error transforming many-to-any : " + hbmCollection.getName(), e, origin() );
					}
				}
				else {
					throw new UnsupportedOperationException( "Unexpected node type - " + hbmCollection );
				}
			}
		}
	}

	private JaxbBasicImpl transformBasicAttribute(final JaxbHbmBasicAttributeType hbmProp, PropertyInfo propertyInfo) {
		final var basic = new JaxbBasicImpl();
		transferBasicAttribute( hbmProp, basic, propertyInfo );
		return basic;
	}

	private void transferBasicAttribute(
			JaxbHbmBasicAttributeType hbmProp,
			JaxbBasicImpl basic,

View on GitHub (pinned to fad1729dce)

Solutions

1. Treat this as an unimplemented feature, not a bug in your mapping: plural <any/> transformation is not implemented
2. Exclude mappings containing <many-to-any> from the transformation and keep them as native hbm.xml (Hibernate 6 binds hbm.xml directly)
3. Or hand-write the equivalent mapping.xml attribute for that collection
4. Or remodel the association as a normal many-to-many/entity hierarchy with an explicit discriminator entity

Example fix

// before: transforming a mapping that contains
// <set name="targets"><key column="..."/><many-to-any meta-type="string">...</many-to-any></set>
transformer.transform(hbmSource); // -> TransformationException

// after: skip transformation for that file, bind it natively
metadataSources.addFile("targets.hbm.xml"); // Hibernate 6 still supports hbm.xml directly

// detect <many-to-any> before running the transformer
var doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(hbmFile);
if (doc.getElementsByTagName("many-to-any").getLength() > 0) {
    throw new UnsupportedOperationException(
        hbmFile + " contains <many-to-any>: plural any transformation is not implemented; bind this file as native hbm.xml");
}

try {
    transformer.transform(hbmSource);
} catch (TransformationException e) {
    if (e.getCause() instanceof UnsupportedOperationException) {
        // plural any is unimplemented - keep this mapping native hbm.xml
        metadataSources.addFile(nativeHbmPath);
    } else { throw e; }
}

When it happens

Trigger: Any hbm.xml containing a <many-to-any> element (heterogeneous collections keyed by a meta-type discriminator) passed through the hbm-to-mapping.xml transformation. The failure is deterministic, not data-dependent.

Common situations: Legacy polymorphic collection mappings (e.g., an 'attachments' set that can hold any entity type); attempting bulk migration of old hbm.xml files to mapping.xml.

Related errors

• Not yet implemented
• Error transforming element-collection :
• Error transforming one-to-many :
• Error transforming many-to-many :
• Unexpected node type -

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/ee34e02309b06320. Report an issue: GitHub.