code: public Jar addEntry(String path, String file) throws IOException {
          try (FileInputStream fos = new FileInputStream(file)) {
              return addEntry(path, fos);
          }
      }
docs: Adds an entry to this JAR.
  
  @param path the entry's path within the JAR
  @param file the path of the file to add as an entry
  @return {@code this}