The fix implemented for issue in org.hibernate.engine.jdbc.internal.ResultSetReturnImpl performs an instanceof check on the statement object to determine if the current statement is an instance of CallableStatement. This presents a potential problem if a framework wraps a statement object in either a proxy or a concrete class that implements both PreparedStatement and CallableStatement.

This can result in wrapped/proxied PreparedStatement objects being incorrectly identified as CallableStatement instances with the end result often being a ClassCastException, AbstractMethodError, or NoSuchMethodException error in the wrapper or proxy.

Since JDK 6 is now a minimum requirement it seems like a more compatible fix would have been to call java.sql.Wrapper.isWrapperFor(CallableStatement.class) method on the statement object to determine the instance type instead of using the instanceof keyword. While I'm not stating that the implemented fix is technically wrong, I believe the use of Wrapper.isWrapperFor would promote improved compatibility across the greatest range of pooling frameworks, JDBC drivers, etc.

Improvement Suggestion:

org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.java