Some experimental SQL client generation code for building client packages and other various half completed trials - (mostly around databases, particular Firebird).
DBPad is a GUI-based SQL client for relational databases. As long as you have a JDBC driver for your DB, you can use DBPad to view or manipulate your data and metadata of your tables.
ProDBA The cross platform Oracle development/administration tool written in Java. Features a powerful SQL editor and schema navigator. Can export dynamic queries to the web.