MethodEntryJoinPoint is a CodeJoinPoint that corresponds
to the beginning of the execution of a method. The
taget of a methodEntryJoinpoint (as obtained by getTarget)
and the object being executed (as obtained by getThis)
are the same object.
Set the argument at position pos to value value.
throws: JVMAIRuntimeException - in case of type mismatches between value and theactual type of the argument at position pos.