code: public static URL locateOnClassPath(String filename) {
      URL result;
      // first try to load from context class loader
      result = Thread.currentThread().getContextClassLoader().getResource(filename);
  
      // next try the current class loader which loaded p6spy
      if (result == null) {
        result = P6Util.class.getClassLoader().getResource(filename);
      }
  
      // finally try the system class loader
      if (result == null) {
        result = ClassLoader.getSystemResource(filename);
      }
  
      return result;
    }
docs: Locates a file on the classpath.
  
  @param filename the relative filePath of the file to load
  @return the URL of the file or null if not found