hibernate/hibernate-orm · error · UnknownUnwrapTypeException

Cannot unwrap to requested type [{}]

Error message

Cannot unwrap to requested type [{}]

What it means

Error "Cannot unwrap to requested type [{}]" thrown in hibernate/hibernate-orm.

Source

Thrown at hibernate-core/src/main/java/org/hibernate/engine/jdbc/connections/internal/UserSuppliedConnectionProviderImpl.java:34

 * exception when a connection is requested, the assumption being that the application
 * is responsible for handing the connection to use to the session.
 *
 * @author Gavin King
 * @author Steve Ebersole
 */
public class UserSuppliedConnectionProviderImpl implements ConnectionProvider {
	@Override
	public boolean isUnwrappableAs(@Nonnull Class<?> unwrapType) {
		return unwrapType.isAssignableFrom( UserSuppliedConnectionProviderImpl.class );
	}

	@Override
	public <T> T unwrap(@Nonnull Class<T> unwrapType) {
		if ( unwrapType.isAssignableFrom( UserSuppliedConnectionProviderImpl.class ) ) {
			return unwrapType.cast( this );
		}
		else {
			throw new UnknownUnwrapTypeException( unwrapType );
		}
	}

	@Override
	public Connection getConnection() throws SQLException {
		throw new UnsupportedOperationException( "The application must supply JDBC connections" );
	}

	@Override
	public void closeConnection(Connection connection) throws SQLException {
		throw new UnsupportedOperationException( "The application must supply JDBC connections" );
	}

	@Override
	public boolean supportsAggressiveRelease() {
		return false;
	}
}

View on GitHub (pinned to fad1729dce)

Solutions

1. Only unwrap to interfaces implemented by UserSuppliedConnectionProviderImpl
2. Avoid unwrap() to unrelated types

When it happens

Trigger: Thrown at hibernate-core/src/main/java/org/hibernate/engine/jdbc/connections/internal/UserSuppliedConnectionProviderImpl.java:34 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/64a4f49a3da1b25d. Report an issue: GitHub.