7.0.1 Installation fails with error 'Unable to register service AuthenticationService'

This error, "Unable to register service AuthenticationService. java.lang.RuntimeException: java.lang.ClassCastException: weblogic.jdbc.wrapper.WrapperSQLXML_oracle_xdb_XMLType cannot be cast to oracle.sql.OPAQUE", has been reported before, and the following solution helped:

...go to Weblogic Admin Console | Services -> Data Sources -> on each datasource Connection Pool -> Advanced -> uncheck Wrap Data Types

Note: The same error and similar solution also posted on the following site (found by Google search):

http://www.soablogs.com/2014/09/oracle-soa-12c-migrating-projects-with.html