JODB is a Development software developed by Mobixess Inc. After our trial and test, the software is proved to be official, secure and free. Here is the official description for JODB:
EditByBSEditor: JODB (Java Objects Database) is the open source object-oriented database somewhat similar to db4objects but entirely oriented for Java community and completely free for personal and commercial use. Being born as part of another private project the database has grown into significant self-contained entity which is now released for public use.
Performance, size and scalability are the cornerstones of this project. The database use soft reference based caches to effectively use available RAM and in the same time minimize footprint when memory is pricey. The queries are optimized to the minimal possible objects instantiations during the search so that Garbage collector will have more time to 'rest' which is especially important for busy server applications (GC is still expensive and its unlikely to change in near future).
# Native queries - concise and type-safe way to ExPress queries directly as Java methods; # Other Queries - the database implements familiar for db4o users (but slightly modified) S.O.D.A. queries, Query-By-Example, Evaluation interface callbacks as well as ability to request object by unique ID; # On demand object activation with configurable depth; # Active object tracking and custom activation; # Acid transactions for reliable data processing; # Transaction rollbacks; # Data File Lock to avoid concurrent modifications by different processes; # Data Backup functionality; # Client/Server network transactions; # Indexing to maximize query performance; you can free download JODB 3.0.0 RC 3 now.