thank you for your response!
This means the physical connection to your database was reset (broken).
I don't think I lies on the connection-pool implementation.
You should first try to find out, why the connection was reset.
Had the database-engine-process or the machine resource-problems at this time?
I don't think so.
We are testing by some simple jUnit tests running on my machine.
The oracle server also runs on my machine.
There is enough free physical RAM on my machine (2.8 of 3.3 GB are used)
Check the database-logs and system logs of the machine where the database runs.
There are no warnings/errors in Windows-EventLog.
There are no *.log files below c:\Programme\Oracle\product\11.1.0\db_1 with current file date+time except a single file with a single line: a current timestamp.
Had the network some problems?
There is no network involved, database and JVM run on the same machine.
I think there is a problem between apache commons dbcp implementation and Oracle's javax.sql.ConnectionPoolDataSource implementation oracle.jdbc.xa.client.OracleXADataSource.
Today I changed the properties of the org.apache.commons.dbcp.datasources.SharedPoolDataSource:
I increased maxActive from 10 to 50 and set maxWait to -1 (= infinite, formerly: 5000 msec).
Now I get complete different errors: A lot of "ORA-01453: SET TRANSACTION muss erste Anweisung der Transaktion sein", and nothing else.
We set the isolation level to 2 (ReadCommitted, property defaultTransactionIsolation of the SharedPoolDataSource instance).
Thanks and regards