Most of the forum questions are about the errors that occur while mapping source to the target! Did we bother to understand what is happening inside? If you did then you can skim this. Did we bother to understand why the RFC Destination AI_RUNTIME_JCOSERVER is very important? If we did not then please read this aloud.
CL_MAPPING_XMS_PLSRV3 is the object that has to be focussed for understanding the complete flow. CALL_RUNTIME is the method which will be executed during the mapping run time. Now if you can go through the method you understand that depending on the mapping type the appropriate mapping methods CALL_JAVA_RUNTIME,MAP_BY_XSLT, MAP_BY_ABAP are called. If you dig dip into the method CALL_JAVA_RUNTIME then you can see that we use the RFC Destination AI_RUNTIME_JCOSERVER while calling Java Runtime FM SMPP_CALL_JAVA_RUNTIME3.
What next? Does it help in knowing this? How we will see which mapping program is getting executed appropraitely? You will understand by digging but let me be modest by sharing the tables SMPPMAP3 and SMPPREL3 and SMPPSPLIT.Please find the screenshot of mapping table SMPPMAP3 which provides the mapping type , mapping program and interface mapping program and name space of each interface developed in SAP XI.
It is also worth looking at the ABAP objects CL_XMS_EPCACHE for getting exchane profile parameters at the ABAP runtime,CL*XMS* and CL*PLSRV*.