code: public void addAll(ClassLoaderFiles files) {
  		Assert.notNull(files, "Files must not be null");
  		for (SourceFolder folder : files.getSourceFolders()) {
  			for (Map.Entry<String, ClassLoaderFile> entry : folder.getFilesEntrySet()) {
  				addFile(folder.getName(), entry.getKey(), entry.getValue());
  			}
  		}
  	}
docs: Add all elements items from the specified {@link ClassLoaderFiles} to this
  instance.
  @param files the files to add