odbc
· IBM Informix® ODBC Driver is a native-protocol that supports the ODBC specification. When you use Informix ODBC Driver in a program to interact with the Informix database, your session connects directly to the database or database server, without a middle tier. You can use the ODBC driver for many different C based applications that access the Informix database server.
Download JD-GUI to open JAR file and explore Java source code file (.class .java)
Click menu "File → Open File..." or just drag-and-drop the JAR file in the JD-GUI window odbc-4.10.10.jar file.
Once you open a JAR file, all the java classes in the JAR file will be displayed.