docs: public static void mkParentDirs(final File file) throws IOException {
          // Create parent directory structure if necessary
          File parentFile = file.getParentFile();
          if (parentFile == null) {
              // File was created with a relative path
              parentFile = file.getAbsoluteFile().getParentFile();
          }
          if (parentFile != null && !parentFile.exists()) {
              if (!parentFile.mkdirs()) {
                  throw new IOException("Unable to create parent directory " +
                          "structure for file " + file.getAbsolutePath());
              }
          }
      }