The driver uses the remote function modules RFC_READ_TABLE, RFC_INSTALL_ABAP_AND_RUN and other functions to get the required information from the SAP system.
The driver accesses the SAP system with an user account which can be restricted by authorizations. Additional authorization checks are included to allow finer restrictions of the remote SAP access.
The performance of the driver corresponds to the performance of the SAP system. The default configuration requires no extensions at the SAP ABAP site. But the extracting programs have to been generated at every request. This is one reason for loosing performance. With extensions at the SAP abap site requests could be more performant. This is planned for the future.
Some features like offset access with max rows per request are built in to save time and memory.
There are some features built in to save memory for equal data over different data cells.
Because of large and wide SAP tables you should define which columns should be extracted with a request.
The driver is not fully jdbc compliant and not certified at the moment. The major goal is to get many tools working with the driver.