On oracle 10 its called classes12.jar, details:
Manifest-Version: 1.0
Specification-Title: Oracle JDBC driver classes for use with JDK12
Sealed: true
Created-By: 1.4.2_08 (Sun Microsystems Inc.)
Implementation-Title: classes12.jar
Specification-Vendor: Oracle Corporation
Specification-Version: Oracle JDBC Driver version - “10.2.0.1.0”
Implementation-Version: Oracle JDBC Driver version - “10.2.0.1.0”
Implementation-Vendor: Oracle Corporation
Implementation-Time: Wed Jun 22 18:51:56 2005
Is there any change you can test with a later driver?, because the exception you get “Stream has already been closed” seems to us something like a driver issue.