Conversion To a Java Database

Has any though been given to convert the database to a Java based one and then the application could be written for cross-platform compatibility. I currently use Linux almost exclusively, and to be able to use RELMA, I load a Windows XP virtual machine in VMware. It would be very convenient to be able to use the RELMA application in Linux. It is possible to import the data into HSQLDB (http://hsqldb.org/) but I was wondering about the possible copyright issues.

Would it be sufficient to convert to a cross-platform database that is Java-accessible, like SQLite or Berkeley DB?