/** Returns a joiner which automatically places {@code separator} between consecutive elements. */
  public static Joiner on(String separator) {
    return new Joiner(separator);
  }

  /** Returns a joiner which automatically places {@code separator} between consecutive elements. */
  public static Joiner on(char separator) {
    return new Joiner(String.valueOf(separator));
  }

  private final String separator;

  /** Returns a joiner which automatically places {@code separator} between consecutive elements. */
  public static Joiner on(String separator) {
    return new Joiner(separator);
  }

  /** Returns a joiner which automatically places {@code separator} between consecutive elements. */
  public static Joiner on(char separator) {
    return new Joiner(String.valueOf(separator));
  }

  private final String separator;