Problem solved, Jboss 3.2.7 seems to work with Informix JDBC 2.21 JC4
I wonder why informix JDBC 3.0 JC1 didn't work, maybe in JBoss 4.
There should be a JDBC versions for JBoss, it would save a lot of time.
With older version of Informix JDBC it was enough to put ifxjdbc.jar into $JBOSS_HOME/server/?/lib.
With 3.0 driver I got same or similar problems and found out, that I also have to put ifxjdbcx.jar into the lib-dir.
I don't know if this is related, but I'm having a similar problem trying to use JDBC 3.0JC1 under Java Web Start where it throws a class cast exception.
I believe they changed the Informix Driver to use the single-parameter version of Class.forName() instead of the three-parameter version that allows the ClassLoader to be passed in. Therefore, if ifxjdbc[x].jar was not loaded by the system ClassLoader, a ClassCastException is thrown.
We don't have paid support at IBM (therefore, we can't even report a problem), although I'm pursuing other channels. If any of you guys has access, you might try reporting the problem to IBM.
I'd love to get this issue resolved.
FYI, 3.00JC2 seems to have resolved the ifxjdbc.jar dependency on ifxjdbcx.jar:
From the release notes's list of fixed bugs:
"171425 IFXJDBCX.JAR IS NOW REQUIRED. JAVA.LANG.NOCLASSDEFFOUNDERROR: COM/INFORMIX/JDBCX/IFXXAREUSABLECONNECTION"
It's available here: