code: public static PathFileObject forJarPath(BaseFileManager fileManager,
              Path path, Path userJarPath) {
          return new JarFileObject(fileManager, path, userJarPath);
      }
docs: Create a PathFileObject for a file in a file system such as a jar file,
  such that the binary name can be inferred from its position within the
  file system.
  
  The binary name is derived from {@code path}.
  The name is derived from the composition of {@code userJarPath}
  and {@code path}.
  
  @param fileManager the file manager creating this file object
  @param path the path referred to by this file object
  @param userJarPath the path of the jar file containing the file system.
  @return the file object