Oracle Loader for Hadoop and Oracle SQL Connector for HDFS work with Oracle Database 12c. For convenience they ship with database jar files, and some of them are version specific. The missing jar files for Oracle Database 12c have to be copied over from the database.
The only required 12c database jars are the Oracle Wallet Manager jars. So if you are using Oracle Wallet Manager, copy the following jars:
The next release of Oracle Big Data connectors will include these 12c jar files so there will be no need for the copy.
All other functionality for these two connectors will work with Oracle Database 12c without change.