hibernate/hibernate-orm · error · MappingException

Unable to instantiate custom AuxiliaryDatabaseObject class [

Error message

Unable to instantiate custom AuxiliaryDatabaseObject class [%s]

What it means

Error "Unable to instantiate custom AuxiliaryDatabaseObject class [%s]" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/boot/model/internal/AuxiliaryDatabaseObjectBinder.java:34

public class AuxiliaryDatabaseObjectBinder {
	public static void processAuxiliaryDatabaseObject(
			MetadataBuildingContext context,
			DatabaseObjectRegistration databaseObjectRegistration) {
		final AuxiliaryDatabaseObject auxDbObject;

		if ( StringHelper.isNotEmpty( databaseObjectRegistration.definition()) ) {
			try {
				auxDbObject = (AuxiliaryDatabaseObject)
						context.getBootstrapContext().getClassLoaderService()
								.classForName( databaseObjectRegistration.definition() )
								.getConstructor()
								.newInstance();
			}
			catch (ClassLoadingException cle) {
				throw cle;
			}
			catch (Exception e) {
				throw new MappingException(
						String.format(
								"Unable to instantiate custom AuxiliaryDatabaseObject class [%s]",
								databaseObjectRegistration.definition()
						)
				);
			}
		}
		else {
			auxDbObject = new SimpleAuxiliaryDatabaseObject(
					context.getMetadataCollector().getDatabase().getDefaultNamespace(),
					databaseObjectRegistration.create(),
					databaseObjectRegistration.drop(),
					null
			);
		}

		if ( !databaseObjectRegistration.dialectScopes().isEmpty() ) {
			if ( auxDbObject instanceof AuxiliaryDatabaseObject.Expandable expandable ) {

View on GitHub (pinned to fad1729dce)

Solutions

1. Ensure the custom AuxiliaryDatabaseObject class has a public no-argument constructor.
2. Check that the class is on the classpath and that its name is spelled correctly in the mapping.

When it happens

Trigger: Hibernate cannot instantiate a user-supplied class named in a mapping annotation.

Common situations: Custom AuxiliaryDatabaseObject or comparator classes that are missing from the classpath, non-public, abstract, or lack a usable no-arg constructor.

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/65502307d44d34aa. Report an issue: GitHub.