There is an open issue with db2 jcc driver when connecting to Informix.
A similar call to getColumns work with both jcc and native jdbc driver:
ResultSet rs = dbMeta.getColumns("demodb", null, "jpataskbean", null); ==> jcc return columns
However, the getImportedKeys does not work with jcc driver:
rs = dbMeta.getImportedKeys("demodb", null, "jpataskbean"); ==> jcc returns empty result set
There can be two possibilities here.
The database metadata methods in the driver are implemented by calling a stored procedure on the server. So the problem could be in the in the stored procedure.
Or since the IDS server supports two different protocols (i.e. sqli and drda). It is possible that getImportedKeys is working in sqli protocol which is used with Informix legacy jdbc driver and not working with drda protocol which is used by JCC driver.
Either way this does seems to be a JCC driver problem.