Could please anybody explain what are pros and cons of this? I mean, without using ORM framework/JPA specification.
It concerns many-to-many and many-to-one relationships between entities. Imagine entity relationship
The kind of transparent persistence technology in JDO has existed since the mid-1980s in C++. JDO has the sole purpose of providing transparent persistence for Java object models. It was not developed as a reaction to EJB. We started JDO in 1999, based on earlier Java persistence efforts in the ODMG, long before EJB existed.