hibernate/hibernate-orm · error · HibernateException

Bytecode enhancement failed because no public, protected or

Error message

Bytecode enhancement failed because no public, protected or package-private default constructor was found for entity '{}' (private constructors don't work with runtime proxies)

What it means

Error "Bytecode enhancement failed because no public, protected or package-private default constructor was found for entity '{}' (private constructors don't work with runtime proxies)" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/proxy/pojo/bytebuddy/ByteBuddyProxyFactory.java:106

		final var hibernateProxy = internal.asHibernateProxy();
		if ( hibernateProxy == null ) {
			throw new HibernateException( "Produced proxy does not correctly implement HibernateProxy" );
		}
		return hibernateProxy;
	}

	/**
	 * This technically returns a HibernateProxy, but declaring that type as the return
	 * type for the newInstance() action triggers an implicit case of type pollution.
	 * We therefore declare it as PrimeAmongSecondarySupertypes, and require the
	 * invoker to perform the narrowing
	 */
	private PrimeAmongSecondarySupertypes getHibernateProxyInternal() throws HibernateException {
		try {
			return (PrimeAmongSecondarySupertypes) proxyClass.getConstructor().newInstance();
		}
		catch (NoSuchMethodException e) {
			throw new HibernateException(
					"Bytecode enhancement failed because no public, protected or package-private default constructor was found for entity '"
							+ entityName + "' (private constructors don't work with runtime proxies)", e );
		}
		catch (Throwable t) {
			throw new HibernateException( "Bytecode enhancement failed for entity '" + entityName + "'", t );
		}
	}

}

View on GitHub (pinned to fad1729dce)

Solutions

1. Add a public, protected, or package-private no-arg constructor to the entity.
2. Avoid private-only constructors on entities that need runtime proxies.

When it happens

Trigger: A dynamic instantiation (select new) target cannot be constructed.

Common situations: Using 'select new SomeClass(...)' where the class is missing or has no matching constructor.

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/beb4c453e41b5080. Report an issue: GitHub.