Should I be using JDBC getNString() instead of getString()?
I have done a test on our application and it seems that getNString() is unnecessary with Java 6, JDBC 6, Oracle JDBC 6 drivers and Oracle 11.1.0.6.0. The test string I used was "Δ, Й, ק, م, ๗, あ, 叶, 葉, and 말", copied from http://en.wikipedia.org/wiki/Unicode.
Most of our data access is done via stored procedures. Java was able to set and retrieve the above test string correctly via setObject() and getString() (not setString() for abstraction reasons), collecting data from the interface and writing it back to the interface as expected.
Hence getString() works ok for Unicode data with Oracle 11g (like SQL Server as in the above link) so we will continue to use this rather than getNString().