It is becoming very popular on the net particularly as a back-end for WWW based applications. Now developed by Hughes Technologies Inc., but still free for personal and non-commercial use. A main-memory DBMS is also available that can be used as a substrate for the calendar system. OO7 Benchmark OO7 benchmark from Wisconsin. Ozone An object-oriented database management system completely implemented in Java and distributed under an open source license.
Source code is available.
A persistent deductive database system from the University of Regina in Canada. Supports inference on nested and complex-object relations with declarative semantics. StoredObjects is an object-oriented database coded in Java. Distributed as open source system under a GNU license scheme. Texas Persistent Store Root directory for the Texas Persistent Store, a DBMS that has a memory-mapped architecture similar to that of ObjectStore.