hibernate/hibernate-orm · error · IllegalStateException

Re-entrant enhancement is not supported: {className}

Error message

Re-entrant enhancement is not supported: {className}

What it means

Error "Re-entrant enhancement is not supported: {className}" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/bytecode/enhance/internal/bytebuddy/ModelTypePool.java:92

	 *
	 * @param classFileLocator
	 * @param coreTypePool
	 * @param cacheProvider
	 * @return
	 */
	static EnhancerClassLocator buildModelTypePool(ClassFileLocator classFileLocator, CoreTypePool coreTypePool, EnhancerCacheProvider cacheProvider) {
		Objects.requireNonNull( classFileLocator );
		Objects.requireNonNull( coreTypePool );
		Objects.requireNonNull( cacheProvider );
		return new ModelTypePool( cacheProvider,
				new EnhancerClassFileLocator( cacheProvider, classFileLocator ), coreTypePool );
	}

	@Override
	public void registerClassNameAndBytes(final String className, final byte[] bytes) {
		final var currentEnhancementState = poolCache.getEnhancementState();
		if ( currentEnhancementState != null ) {
			throw new IllegalStateException( "Re-entrant enhancement is not supported: " + className );
		}
		final var state =
				new EnhancerCacheProvider.EnhancementState( className,
						new ClassFileLocator.Resolution.Explicit( Objects.requireNonNull( bytes ) ) );
		// Set the state first because the ClassFileLocator needs this in the doDescribe() call below
		poolCache.setEnhancementState( state );
		state.setTypePoolResolution( doDescribe( className ) );
	}

	@Override
	public void deregisterClassNameAndBytes(String className) {
		poolCache.removeEnhancementState();
	}

	@Override
	public ClassFileLocator asClassFileLocator() {
		return locator;
	}

View on GitHub (pinned to fad1729dce)

Solutions

1. Avoid triggering enhancement of a class from within its own enhancement; check for circular class-loading during the enhancement run.

Example fix

Avoid triggering enhancement of a class from within its own enhancement; check for circular class-loading during the enhancement run.

When it happens

Trigger: Bytecode enhancement, proxy creation, or lazy interception is applied to an incompatible class or configuration.

Common situations: Build-time enhancement with module-system restrictions, mismatched Hibernate versions between build and runtime, or hibernate.bytecode.provider=none with a model that needs proxies.

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/eac6069aa99d7501. Report an issue: GitHub.