Quantum is a database plugin for Eclipse (needs GEF, Point Eclipse at http://quantum.sourceforge.net/update-site). It currently supports most databases with a JDBC driver. It shows tables, views, and sequences in a tree format and provides an SQL editor
SQL Star, a SQL client provides a common Graphical User Interface (GUI) for all database servers (like, oracle, microsoft sql server, mysql etc.,) using JAVA JDBC 3.0 API With type 4 driver.
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.
ViennaSQL is a GUI SQL client written in 100% Java. ViennaSQL can communicate with any database that has a JDBC driver. It should run anywhere Java runs.