TREX can communicate with the application using it by means of an HTTP connection or an RFC connection:
ABAP application accesses TREX by means of an ABAP client (RFC connection)
As a rule, ABAP applications communicate with the TREX servers through the TREX ABAP client using the RFC/SNC protocol. Communication takes place using an Gateway and an RFC server.
Java application accesses TREX by means of a Java client (HTTP connection)
As a rule, Java applications communicate with the TREX servers by means of the TREX Java client using the HTTP or HTTPS protocol. This communication takes place using a Web server that is enhanced with TREX-specific functions.
There are therefore two procedures for connecting TREX with the application using it: