Perst - object-oriented embedded database
Perst is McObject's open source, dual license, object-oriented embedded database system (ODBMS). Perst gives developers the ability to sort, store and retrieve objects in their applications with maximum speed and with low memory and storage overhead, while leveraging the object-oriented paradigm of Java and C#. It is available in one edition developed as an all-Java embedded database, and another implemented in C# (for Microsoft .NET Framework applications).
Perst’s also include garbage collection, schema evolution, a “wrapper” that provides a SQL-like database interface (SubSQL), XML import/export, database replication, support for large databases, and more.