The REST JDBC driver provides a well-known and common interface for RESTful access of the database. It allows access to cloud databases for JDBC based applications including tools such as SQL developer and SQL CL, without the need for interaction with raw REST calls or a different separate SDK
At a high-level, an application communicates with ORDS using the REST JDBC driver. ORDS in turn uses the native driver to send to and receive information from the Database.
JDBC based applications should be able to use the REST JDBC driver as is, without rewriting much / any code and only swapping out the driver name and the database url.