jEdit with jGoodies
Jython is great
Fake J2EE is not that bad!
Respecting SQL
Jodd
In the spirit of SquirrelSQL client, here is another one - iSQL-Viewer. Java based GUI for JDBC data sources. Need to try this out, for one reason.
It looks like it can be scripted using Jython and Bean Scripting Framework.
jFaceDbc is another JDBC client application written in Java that will allow you to view the structure of a JDBC compliant database, issuing SQL commands, etc. The GUI is based on JFace and SWT libraries from the Eclipse Project, rather than Swing. It can be used as a standalone application or as an Eclipse plugin.