According to the Inquirer, OpenOffice.org 2.0 makes use of HSQL Embedded database engine for its database component. The issue is that HSQL is written in Java and though require a Java runtime, which is not free, given the current state of the Free java reimplementation. The source code license has not changed, but this dependency is probably not the best choice, even thought it is also Free Software. Probably because Sun and Java are so closely related.