Watson Explorer Engine does not ship with the JDBC drivers for DB2 due to licensing issues. However, all DB2 installations in which you have installed JDBC support include the JAR files that Watson Explorer Engine requires in order to be able to crawl a DB2 installation. In order to crawl a DB2 instance, you must copy these files into the appropriate directory in your installation so that Watson Explorer Engine can use them.
To enable Watson Explorer Engine to crawl a DB2 installation, locate the db2jcc.jar and license (typically, db2jcc_license_cu.jar) JAR files in your DB2 installation, and copy those files to the lib/java subdirectory of your Watson Explorer Engine installation directory.
You should now be able to crawl a DB2 database once you have configured the keyed database seed, as discussed in Configuring Custom SQL Seeds.