calling isClosed appears to hang

We are using pgjdbc2.jar and notice that the isClosed method of the Connection
class hangs.  I read somewhere that the isClosed method is actually implemented
to make a sql call to the postmaster to test the connection and respond accordingly.
Is there some where in that code where the sql request could hang?

Any help would be appreciated.

Sincerely,

  Warren Little
  IT Manager
  Security Lending Wholesale