hibernate/hibernate-orm · error · IllegalArgumentException

Unsupported user-defined type:

Error message

Unsupported user-defined type: 

What it means

The standard user-defined-type exporter only knows how to render UserDefinedObjectType and UserDefinedArrayType. Any other UserDefinedType subtype reaching getSqlCreateStrings is rejected with this IllegalArgumentException naming the type. This is effectively an extension/programming error: custom code or a custom dialect supplied a UserDefinedType implementation the standard exporter cannot handle.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/tool/schema/internal/StandardUserDefinedTypeExporter.java:44

	protected final Dialect dialect;

	public StandardUserDefinedTypeExporter(Dialect dialect) {
		this.dialect = dialect;
	}

	@Override
	public String[] getSqlCreateStrings(
			UserDefinedType userDefinedType,
			Metadata metadata,
			SqlStringGenerationContext context) {
		if ( userDefinedType instanceof UserDefinedObjectType userDefinedObjectType ) {
			return getSqlCreateStrings( userDefinedObjectType, metadata, context );
		}
		else if ( userDefinedType instanceof UserDefinedArrayType userDefinedArrayType ) {
			return getSqlCreateStrings( userDefinedArrayType, metadata, context );
		}
		else {
			throw new IllegalArgumentException( "Unsupported user-defined type: " + userDefinedType );
		}
	}

	public String[] getSqlCreateStrings(
			UserDefinedObjectType userDefinedType,
			Metadata metadata,
			SqlStringGenerationContext context) {
		final var typeName = new QualifiedNameParser.NameParts(
				Identifier.toIdentifier( userDefinedType.getCatalog(), userDefinedType.isCatalogQuoted() ),
				Identifier.toIdentifier( userDefinedType.getSchema(), userDefinedType.isSchemaQuoted() ),
				userDefinedType.getNameIdentifier()
		);

		try {
			final String formattedTypeName = context.format( typeName );
			final var createType =
					new StringBuilder( "create type " )
							.append( formattedTypeName )

View on GitHub (pinned to fad1729dce)

Solutions

1. Model custom UDTs as UserDefinedObjectType (standard CREATE TYPE shape) or UserDefinedArrayType so the standard exporter understands them.
2. Override the dialect's UserDefinedTypeExporter to render your custom type kind and ensure your dialect routes export calls to it instead of the standard exporter.
3. Exclude the custom type from hbm2ddl generation and create it with an external migration script.

Example fix

// before
public class MyGeometryType implements UserDefinedType { ... } // rejected by the exporter

// after
public class MyGeometryType extends UserDefinedObjectTypeImplementor { ... } // standard CREATE TYPE path

if (udt instanceof UserDefinedObjectType || udt instanceof UserDefinedArrayType) {
    exporter.getSqlCreateStrings(udt, metadata, context);
} else {
    // route to your dialect-specific exporter or skip hbm2ddl for this type
}

static boolean isStandardExportableUdt(UserDefinedType udt) {
    return udt instanceof UserDefinedObjectType || udt instanceof UserDefinedArrayType;
}

try {
    exporter.getSqlCreateStrings(userDefinedType, metadata, context);
} catch (IllegalArgumentException e) {
    if (e.getMessage() != null && e.getMessage().startsWith("Unsupported user-defined type:")) {
        // extend UserDefinedObjectType/UserDefinedArrayType or bypass standard export for this type
    } else { throw e; }
}

When it happens

Trigger: Passing a custom UserDefinedType implementation (neither UserDefinedObjectType nor UserDefinedArrayType) into schema export: a custom dialect or metadata contributor registering its own UDT kind, or direct programmatic calls to StandardUserDefinedTypeExporter.getSqlCreateStrings with a hand-rolled type object.

Common situations: Teams extending Hibernate 6 UDT support with internal type hierarchies; prototypes implementing UserDefinedType directly instead of extending the object/array base types; misrouted exporter usage where a dialect-specific exporter was expected to handle the call but the standard one received it.

Related errors

• Error creating SQL create commands for UDT :
• Decomposition not supported for %s
• Database does not support user-defined types (remove '@Struc
• Struct [%s] is defined by multiple components %s with differ
• Struct [%s] of class [%s] is defined by multiple components

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/98ed7c5f74c7ac40. Report an issue: GitHub.