The problem was the connection document was in wrong folder. Now it is in correct folder WebContent/WEB-INF/jdbc, but the error below was displayed in log:
09/15/2014 16:59:12 HTTP JVM: com.ibm.db2.jcc.c.SqlException: [ibm] [db2] [jcc]   The version of the IBM Universal JDBC driver in use is not is licensed for connectivity to banks QDB2 data.
09/15/2014 16:59:12 HTTP JVM: To connect to this DB2 server, get a licensed version of IBM DB2 Universal Driver for JDBC and SQLJ copy.
09/15/2014 16:59:12 HTTP JVM:. An appropriate license file db2jcc_license _ * jar for this target platform must be installed in the classpath of the application.
09/15/2014 16:59:12 HTTP JVM: Connectivity banks QDB2 data is activated by one of the following license files: [db2jcc_license_cisuz.jar].
Where can I download the correct driver? The DB2 version is 18.104.22.1685.822.