AR for Java; ActiveObjects is an intuitive, pure-Java ORM. AO is designed from the ground up to be extremely simple and easy to use from an API standpoint. AO can be used with either an existing database schema, or it can auto-generate the database schema from the user-specified entity interfaces. ActiveObjects also supports Rails-style database migrations, allowing incremental changes and refactoring of the database schema without data loss.AO can perform better than data mapper ORMs due to its natural use of lazy-loading coupled with sophisticated caching mechanisms. However, performance is not the primary design goal of the project. Rather, the intention is to create an ORM which is powerful and yet extremely natural to use and integrate into your project. This design has lead to certain performance benefits (such as lazy-loading), but on the whole, data mapper ORMs are inherently slightly more performant than AO