Due to the distribution policy of Oracle JDBC driver, it can only be downloaded manually from http://www.oracle.com/technetwork/database/features/jdbc/index-091264.html. After downloading, copy ojdbc6.jar file into the lib subfolder in Studio and the lib subfolder of the installed Tomcat server. Then you need to stop Studio, stop Gradle daemon by executing gradle --stop in the command line, then start Studio again.
