public UUID subjectIdPerCall(@Nullable UUID subjId){
  if (subjId != null)   return subjId;
  return subjectIdPerCall(subjId,operationContextPerCall());
}

public UUID subjectIdPerCall ( @ Nullable UUID subjId ) { if ( subjId != null ) return subjId ; return subjectIdPerCall ( subjId , operationContextPerCall ( ) ) ; }
gets subject id per call .
