Fastest way to check aliveness of connection

[Daniel Migowski <dmigowski(at)ikoffice(dot)de>]

Hello,

I want to implement a c3p0 ConnectionTester and now need a fast way to 
check for the alivelyness of a Connection. Currently I issue a "select 
1" to the database and if I don't get an exception I assume the 
connection is still alive.

Is there a faster way? How can I check if the underlying socket is still 
alive without doing a JDBC request? This has to work only with 
PostgreSQL JDBC, so I can cast to any postgres interface available.

With best regards,
Daniel Migowski