code: public static Workspace loadWorkspaceFromJson(File file) throws Exception {
          if (file == null) {
              throw new IllegalArgumentException("The path to a JSON file must be specified.");
          } else if (!file.exists()) {
              throw new IllegalArgumentException("The specified JSON file does not exist.");
          }
  
          return new JsonReader().read(new FileReader(file));
      }
docs: Loads a workspace from a JSON definition saved as a file.
  
  @param file a File representing the JSON definition
  @return a Workspace object
  @throws Exception if something goes wrong