How to simulate database failure to test 2-phase commit in Java

I am implementing a 2-phase commit involving distributed resources. How do I simulate the failure of a participating database ? Pulling out the network cable doesn't work as it causes table deadlock. I am currently using hooks in my application code which throw StaleConnectionException at different points like before query execution, after query execution. My concern with this approach is:

• Is there a better way to simulate the DB failure?
• What happens to the connection object when DB connection goes bad? Does it retain its value or does it become null?
• What actually happens when application tries to reconnect to DB?What value does connection object get?Does it use an existing value from the connection pool?

I would also like to test at intermediate points like during query execution, during commit (after prepare is sent, etc). Right now I put application into debug mode and step into the function call and pull the plug in between. But this approach is manual and won't work for a scale testing.

Is there a simulator/emulator or tool which can help me do this?