hibernate/hibernate-orm · error · MappingException

Attempt to use multiple inheritance strategies : %s & %s

Error message

Attempt to use multiple inheritance strategies : %s & %s

What it means

Error "Attempt to use multiple inheritance strategies : %s & %s" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/boot/jaxb/hbm/transform/HbmXmlTransformer.java:1146

			defineInheritance( mappingEntity, InheritanceType.TABLE_PER_CLASS );
		}

		for ( var hbmQuery : hbmClass.getQuery() ) {
			// Tests implied this was the case...
			final String name = hbmClass.getName() + "." + hbmQuery.getName();
			mappingXmlBinding.getRoot().getNamedQueries().add( transformNamedQuery( hbmQuery, name ) );
		}

		for ( var hbmQuery : hbmClass.getSqlQuery() ) {
			// Tests implied this was the case...
			final String name = hbmClass.getName() + "." + hbmQuery.getName();
			mappingXmlBinding.getRoot().getNamedNativeQueries().add( transformNamedNativeQuery( hbmQuery, name ) );
		}
	}

	private void defineInheritance(JaxbEntityImpl mappingEntity, InheritanceType strategy) {
		if ( mappingEntity.getInheritance() != null && mappingEntity.getInheritance().getStrategy() != strategy ) {
			throw new MappingException(
					String.format(
							Locale.ROOT,
							"Attempt to use multiple inheritance strategies : %s & %s",
							mappingEntity.getInheritance().getStrategy(),
							strategy
					),
					origin()
			);
		}
		else {
			mappingEntity.setInheritance( new JaxbInheritanceImpl() );
			mappingEntity.getInheritance().setStrategy( strategy );
		}
	}

	private void transferDiscriminatorSubclass(
			JaxbHbmDiscriminatorSubclassEntityType hbmSubclass,
			JaxbEntityImpl subclassEntity,

View on GitHub (pinned to fad1729dce)

Solutions

1. Use exactly one inheritance strategy per entity hierarchy (SINGLE_TABLE, JOINED, or TABLE_PER_CLASS); remove the conflicting strategy annotations/elements.
2. Check the hbm.xml being transformed for mixed <joined-subclass> and <subclass>/<union-subclass> usage in one hierarchy.
3. Restructure the hierarchy if two strategies were genuinely needed.

When it happens

Trigger: An entity hierarchy mixes different inheritance mapping strategies.

Common situations: Using different <subclass>/<joined-subclass>/<union-subclass> styles, or @Inheritance strategies, within a single hierarchy.

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/e7fe6e7ac58a23a7. Report an issue: GitHub.