they use OrientDB, I have used it in my past GUI Swing project: https://github.com/jjk3/scrape-it-screen-scraper https://github.com/jjk3/scrape-it-screen-scrape

they use OrientDB, I have used it in my past GUI Swing project: https://github.com/jjk3/scrape-it-screen-scraper https://github.com/jjk3/scrape-it-screen-scraper OrientDB was a clear win for me because it was open source and free while other Java Object databases had license fees attached in tiny letters. The author of OrientDB was very helpful too on the google discuss groups. OrientDB included everything I wanted, SQL for POJO storage, server or file storage DB.