If you are working with HSQLDB v1.8 and you don’t see changes written to disk or if after you app runs you can view your data it’s because HSQL since 1.7 is not closing the database after the last connection is closed.
To fix this append the following to your JDBC url.
;shutdown=true
See the following link for more details:
http://blog.taragana.com/index.php/archive/hsqldb-database-connection-close-doesnt-write-to-disk-solution/