code: protected void loadCacheMapping() {
  		File f = new File(getCacheFilePath());
  		if (f.exists()) {
  			try(InputStream is = new FileInputStream(f); BufferedReader rd = new BufferedReader(new FileReader(f))) {
  				cacheProperties.load(is);
  				for (Enumeration<?> properyNames = cacheProperties.propertyNames(); properyNames.hasMoreElements();) {
  					String propName = (String) properyNames.nextElement();
  					if (propName.startsWith(JAWR_MAPPING_PREFIX)) {
  
  						String value = cacheProperties.getProperty(propName);
  
  						String resourceMapping = propName.substring(JAWR_MAPPING_PREFIX.length());
  						String[] mappings = value.split(SEMICOLON);
  						List<FilePathMapping> fMappings = new CopyOnWriteArrayList<>();
  
  						// TODO check the use of mappingModified
  						boolean mappingModified = true;
  						for (String fmapping : mappings) {
  							String[] mapping = fmapping.split(MAPPING_TIMESTAMP_SEPARATOR);
  							long lastModified = Long.parseLong(mapping[1]);
  							String filePath = mapping[0];
  							if (rsHandler.getLastModified(filePath) != lastModified) {
  								mappingModified = false;
  								break;
  							}
  							FilePathMapping fmap = new FilePathMapping(filePath, lastModified);
  							fMappings.add(fmap);
  						}
  
  						if (mappingModified) {
  							linkedResourceMap.put(resourceMapping, fMappings);
  						}
  					}
  				}
  
  			} catch (IOException e) {
  				throw new BundlingProcessException("Unable to initialize " + getName() + " Generator cache", e);
  			}
  		}
  	}
docs: Loads the less file mapping