hibernate/hibernate-orm · error · IllegalArgumentException

Id generator object or name is null

Error message

Id generator object or name is null

What it means

addIdentifierGenerator is the registration point for named id generators (sequence/table style definitions). It throws IllegalArgumentException 'Id generator object or name is null' when called with a null IdentifierGeneratorDefinition or one whose name is null, before any map interaction happens.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/boot/internal/InFlightMetadataCollectorImpl.java:643

		if ( name == null ) {
			throw new IllegalArgumentException( "null is not a valid generator name" );
		}
		return idGeneratorDefinitionMap.get( name );
	}

	@Override
	public java.util.Collection<Table> collectTableMappings() {
		final ArrayList<Table> tables = new ArrayList<>();
		for ( Namespace namespace : getDatabase().getNamespaces() ) {
			tables.addAll( namespace.getTables() );
		}
		return tables;
	}

	@Override
	public void addIdentifierGenerator(IdentifierGeneratorDefinition generator) {
		if ( generator == null || generator.getName() == null ) {
			throw new IllegalArgumentException( "Id generator object or name is null" );
		}
		else if ( !generator.getName().isEmpty()
					&& !defaultIdentifierGeneratorNames.contains( generator.getName() ) ) {
			final var old = idGeneratorDefinitionMap.put( generator.getName(), generator );
			if ( old != null && !old.equals( generator ) ) {
				if ( bootstrapContext.getJpaCompliance().isGlobalGeneratorScopeEnabled() ) {
					throw new IllegalArgumentException( "Duplicate generator name '" + old.getName()
							+ "'; you will likely want to set the property '"
							+ JpaComplianceSettings.JPA_ID_GENERATOR_GLOBAL_SCOPE_COMPLIANCE
							+ "' to false " );
				}
				else {
					BOOT_LOGGER.duplicateGeneratorName( old.getName() );
				}
			}
		}

	}

View on GitHub (pinned to fad1729dce)

Solutions

1. Always construct the definition with a name: new IdentifierGeneratorDefinition("user_seq", strategy, params)
2. Null-check the generator and its name before calling addIdentifierGenerator
3. Skip registration entirely for null definitions rather than forwarding them

Example fix

// before: definition without a name
IdentifierGeneratorDefinition def =
        new IdentifierGeneratorDefinition(null, "sequence", params);

// after
IdentifierGeneratorDefinition def =
        new IdentifierGeneratorDefinition("user_seq", "sequence", params);
collector.addIdentifierGenerator(def);

if (generator == null || generator.getName() == null) {
    throw new IllegalArgumentException("id generator requires a name: " + generator);
}
collector.addIdentifierGenerator(generator);

static boolean isRegistrableGenerator(IdentifierGeneratorDefinition g) {
    return g != null && g.getName() != null;
}

When it happens

Trigger: Programmatically adding an IdentifierGeneratorDefinition that was built without a name (e.g. new IdentifierGeneratorDefinition(null, strategy, params)), or a null definition forwarded by an integration; the guard is at InFlightMetadataCollectorImpl.java:645-647.

Common situations: Custom bootstrap code copying generator definitions between metadata instances; integrations constructing definitions from partial configuration; refactoring that dropped the name argument.

Related errors

• null is not a valid generator name
• Filter definition object or name is null: %s
• Fetch profile object or name is null: %s
• null is not a valid query name
• The specified package name cannot be null

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/5e664709e2bed170. Report an issue: GitHub.