public void init() throws IOException{
			if(targetDirs.size() == 0){
				logger.error("No target is set");
				return;
			}
			
            this.filesInTargetsNotInSource = new ArrayList<ArrayList<Path>>();
            this.filesInSourceNotInTargets = new ArrayList<ArrayList<Path>>();
            
            for(Path targetDir : targetDirs){
            	this.filesInTargetsNotInSource.add(collectRelativeFilesInSrc1NotPresentInSrc2(targetDir,sourceDir));
            	this.filesInSourceNotInTargets.add(collectRelativeFilesInSrc1NotPresentInSrc2(sourceDir,targetDir));
            }
	}