A couple of important notes about ODBC DSN's:
First, make sure that you create a "System" DSN whenever the calling code is located inside a service. Since you're using a Web server (
Tomcat or something similar I assume?) and thus probably running it as a service, you need to make sure your DSN is a System DSN, NOT User. The service cannot access a user DSN unless you happen to create the user DSN as the same user that the service is running as. However, it's best just to make it a system DSN. Also, you can use a File DSN if you need to, as they work like system DSNs.
Second, DSN names are case sensitive. So, if your DSN is named "Test" and you try to use the connect URL of jdbc:odbc:
TEST, it will fail.