Advertencia no pool de conexão

Estou recebendo bastante está mensagem,

o que poderia está causando o problema no pool de conexão ?

ADVERTÊNCIA: problem closing pooled connection java.sql.SQLRecoverableException: Erro de ES: Socket closed at oracle.jdbc.driver.T4CConnection.logoff(T4CConnection.java:556) at oracle.jdbc.driver.PhysicalConnection.close(PhysicalConnection.java:3984) at org.hibernate.connection.DriverManagerConnectionProvider.close(DriverManagerConnectionProvider.java:152) at org.hibernate.connection.DriverManagerConnectionProvider.finalize(DriverManagerConnectionProvider.java:142) at java.lang.System$2.invokeFinalize(Unknown Source) at java.lang.ref.Finalizer.runFinalizer(Unknown Source) at java.lang.ref.Finalizer.access$100(Unknown Source) at java.lang.ref.Finalizer$FinalizerThread.run(Unknown Source) Caused by: java.net.SocketException: Socket closed at java.net.SocketOutputStream.socketWrite(Unknown Source) at java.net.SocketOutputStream.write(Unknown Source) at oracle.net.ns.DataPacket.send(DataPacket.java:210) at oracle.net.ns.NetOutputStream.flush(NetOutputStream.java:230) at oracle.net.ns.NetInputStream.getNextPacket(NetInputStream.java:312) at oracle.net.ns.NetInputStream.read(NetInputStream.java:260) at oracle.net.ns.NetInputStream.read(NetInputStream.java:185) at oracle.net.ns.NetInputStream.read(NetInputStream.java:102) at oracle.jdbc.driver.T4CSocketInputStreamWrapper.readNextPacket(T4CSocketInputStreamWrapper.java:124) at oracle.jdbc.driver.T4CSocketInputStreamWrapper.read(T4CSocketInputStreamWrapper.java:80) at oracle.jdbc.driver.T4CMAREngine.unmarshalUB1(T4CMAREngine.java:1137) at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:290) at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:192) at oracle.jdbc.driver.T4C7Ocommoncall.doOLOGOFF(T4C7Ocommoncall.java:61) at oracle.jdbc.driver.T4CConnection.logoff(T4CConnection.java:543) ... 7 more