code: public URL findResource(URL source, String name)
      {
          return findResource(source, name, new HashSet<>(), null);
      }
docs: Fined resource with given name at the given source URL. If the URL points to a directory, the name is the file
  path relative to this directory. If the URL points to a JAR file, the name identifies an entry in that JAR file.
  If the URL points to a JAR file, the resource is not found in that JAR file, and the JAR file has Class-Path
  attribute, the JAR files identified in the Class-Path are also searched for the resource.
  
  @param source the source URL
  @param name the resource name
  @return URL of the resource, or null if not found