JDOInstruments is an embedded object oriented database programmed in java, it is also an implementation of Sun’s Java Data Objects (JDO) specification for the transparent persistence of Java objects.
Because of this, it doesn’t need a JDBC driver or a relational database. It uses its own object store thus it allows storage and retrieval of persistent data with little work from you.
It is free and Our license is GNU GPL providing the code and executables (JARs) free of charge. You are free to use JDOInstruments in your projects.