hibernate/hibernate-orm · error · IllegalArgumentException

Class '{object.getClass()}' is not an entity class

Error message

Class '{object.getClass()}' is not an entity class

What it means

Error "Class '{object.getClass()}' is not an entity class" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/internal/SessionImpl.java:1727

		}
		catch ( RuntimeException e ) {
			throw getExceptionConverter().convert( e );
		}
	}

	private void assertInstanceOfEntityType(Object object) {
		try {
			final String entityName = getEntityNameResolver().resolveEntityName( object );
			if ( entityName == null ) {
				throw new IllegalArgumentException( "Could not resolve entity name for class '"
													+ object.getClass() + "'" );
			}
			else {
				requireEntityPersister( entityName );
			}
		}
		catch ( HibernateException e ) {
			throw new IllegalArgumentException( "Class '" + object.getClass()
												+ "' is not an entity class", e );
		}
	}

	@Override
	@Deprecated(forRemoval = true)
	@SuppressWarnings("removal")
	public boolean contains(@Nonnull String entityName, @Nonnull Object object) {
		return contains( object );
	}

	@Override
	@Nonnull
	public ProcedureCall createStoredProcedureCall(@Nonnull String procedureName) {
		checkOpen();
//		checkTransactionSynchStatus();
		return super.createStoredProcedureCall( procedureName );
	}

View on GitHub (pinned to fad1729dce)

Solutions

1. Mark the class as an entity (@Entity or XML mapping) and ensure it is scanned/registered with the SessionFactory before use.
2. Pass an actual entity class or instance rather than a DTO, proxy base, or unmapped class.

When it happens

Trigger: Thrown at hibernate-core/src/main/java/org/hibernate/internal/SessionImpl.java:1727 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of hibernate/hibernate-orm@fad1729dce (2026-08-22). Data as JSON: /api/errors/160e195b15ba8b3c. Report an issue: GitHub.