Message mapping execution?
The message processing(pipeline steps) happens in the abap stack,then how request message mapping(one of the pipeline step)happens in abap stack,as message mapping should execute in java stack,
SAP PI replied
Message mapping depends on the mapping technology:
i. Message, Java & XSLT (under Imported Archives) mappings are executed at Java stack;
ii. ABAP & XSLT (in ABAP stack) mappings are executed at ABAP stack.
The Integration Engine that processes the message pipeline (which runs in ABAP stack) will either execute a JCo call (using RFC Dest AI_RUNTIME_JCOSERVER) to the Java Stack to execute the mapping or, in the 2nd case, execute the mapping ABAP function directly.
The pipeline steps can be seen in the transaction SXMB_ADM ->Display Pipeline Definition
Here you have a good overview: