db server processes hanging around

hi

we are running out of database connections.

we are using pg 9.0.6 on linux centos 5.7 64bit.
we are not using any go-between connection pools such as pgbouncer or
pgpool - connections occur directly from client to database.
the connection setup on the client (java) is default, only providing
(user,password,dbhost,dbname).

we have about 10 developers developing java thru IDEA who start/stop the
local tomcat server frequently.
i have observed that tomcat doesn't disconnect from pg cleanly when they
cycle, and the server processes persist for a long time.
I have had them reduce their local connection factory pool size to 1 (this
helped) and increased our max_connection value to 1000.
yet the problem persists.

I have noticed that the server processes do die "after some time" - due to
inactivity?
we are looking for a way to control server processes better than we are
doing now.

thnx for your time.
mr