JOOQ is completely free to use for Open Source databases. Here is a list: <a href="http:&#x2F;&#x2F;www.jooq.org&#x2F;legal&#x2F;licensing#databases" rel="nofollow">http:&#x2F;&#x2F;www.jooq.org&#x2F;legal&#x2F;licensing#databases</a>