Update JDBC Drivers
Ensure the H4A installer (WLSH4A or WASH4A) has the latest JDBC driver files for the currently supported database versions. These files should be in the subdirectory called JDBC under the WLSH4A and WASH4A directories. The drivers are copied to the Development Clients during the H4A installations and are used by the H4A web clients to connect to various databases. This JDBC subdirectory must contain only the latest drivers and no obsolete drivers.
Running the latest OUI version 12.2 installer to install a package on an existing Development Client that previously used OUI version 11.2 could cause issues. Although not required, Oracle highly recommends that the previous Development Client installation be saved via Snapshot or uninstalled before running a new installer.