private ENTITY merge(Manager<ENTITY> manager, ENTITY entity) {
        final Set<ENTITY> result = MergeUtil.merge(manager, singleton(entity));
        if (result.size() != 1) {
            throw new SpeedmentException("Unable to merge entity of type " + entity.getClass().getName());
        }
        return result.iterator().next();
    }
Default implementation of the {@link SqlPersistence}-interface.

@param <ENTITY>  the entity type

@author  Emil Forslund
@author  Dan Lawesson
@since   3.0.1
runtime-parent/runtime-core/src/main/java/com/speedment/runtime/core/internal/component/sql/SqlPersistenceProviderImpl.java