This distribution comes with the 3rd party libraries listed below.
These are not needed for plain db4o operation, but only for specific use cases involving native query optimization.

bloat-1.0.jar
http://www.cs.purdue.edu/s3/projects/bloat/
Needed for bytecode analysis during native query optimization. Must be on the runtime classpath for optimization at load or query execution time, must be present during the Ant build for class file optimization.

ant.jar
http://ant.apache.org/
Needed for the native query optimization Ant task.

Please refer to the license files for these libraries as well as to the Licensing and Native Query Optimization chapter in the tutorial for further information.