Application server connection pool settings that are of concern to the Software Architect:Aged Timeout

Aged Timeout: default value is zero which implies no timeout.This is the maximum time that Websphere will use a given connection.  So, if a connection stays in use past this time, without an intervening idle window >= the Unused timeout -- Websphere will simply recycle this connection.

Again this setting depends on your application, but 9000 seconds or 2.5 hours is a good starting point.  No specific reason, it just feels good to know that connections are getting closed every so often so any memory leak in the connection either in Websphere or in Oracle is getting cleared. 

It also flags any connections on the db server that are older than this timeout for further investigation.

I am presuming you are well aware that ResultSets, Prepared Statements. Callable Statements are to be closed after use.  Closing the connection will not necessarily close them.  These timeouts will not protect you in the event you are not doing this.  I don't even mention the vanilla Statement, on the assumption that you are savvy enough to never use it in your J2EE application.