JdbcProxy is a JDBC 2.0 driver that can help debug or test applications. The driver can wrap another JDBC driver to debug the JDBC calls done by the application. The driver can also emulate another JDBC driver to test the application without a database.
NetworkTools has 2 components: A protocol analyzer which plays a TCP client or server or pipeline, which sits between a client and server and shows how they communicate. A port scanner can scan a range of IP addresses and ports. See screenshots.