code: protected static URL getUrlForStringFromClasspathAsFileOrUrl(String logbackConfigurationFile) {
  
          URL url = null;
  
          try {
              url = Resources.getResource(logbackConfigurationFile);
          } catch (IllegalArgumentException ex) {
              // doing nothing intentionally..
          }
  
          if (url == null) {
              // configuring from file:
              try {
                  File file = new File(logbackConfigurationFile);
                  
                  if (file.exists()) {
                      url = new File(logbackConfigurationFile).toURI().toURL();
                  }
                  
              } catch (MalformedURLException ex) {
                  // doing nothing intentionally..
              }
  
          }
  
          if (url == null) {
              try {
                  // we assume we got a real http://... url here...
                  url = new URL(logbackConfigurationFile);
              } catch (MalformedURLException ex) {
                  // doing nothing intentionally..
              }
  
          }
  
          return url;
      }
docs: Looks up a potential file from
  1) The classpahth
  2) From the filesystem
  3) From an URL
  
  @param logbackConfigurationFile
  @return null if not found or a valid url created from the logbackConfigurationFile