will IS clear the bad JDBC connection out of the JDBC pool?

Hello, all
I’d like to know whether IS will clear the bad jdbc connnection from JDBC pool. If there is a network problem, and a jdbc connection was in use at that time, what will IS do after the network problem? Will IS clear the bad connection?
We’ve met such problem. The adapter service works well for a long time. But one day, when we run the service in developer, we met this error :com.wm.app.b2b.server.ServiceException: [ART.117.4002] Adapter Runtime (Adapter Service):closed connection. And if we reenable the jdbc connection ,everything works fine. So i think maybe there is something wrong with JDBC connection pool.
And another problem, we just couldn’t run any adapter service and we can’t disable jdbc connection so the only thing we could do is restart IS server. error log: java.sql.SQLException: ORA-12547: TNS:lost contact. Maybe there is some network problem at that time but the database works well when we run the adapter service.
BTW, we are using OCI for jdbc connection since the database is oracle rac.
Any comments are highly appreciate.

What are your min pool sizes?

Enable Connection Pooling true
Minimum Pool Size 0
Maximum Pool Size 20
Pool Increment Size 1
Block Timeout (msec) 1000
Expire Timeout (msec) 1000
Startup Retry Count 0
Startup Backoff Timeout (sec) 10