Method advance

corpus/java/training/guava/io/MultiReader.java:45–50

Closes the current reader and opens the next one, if any.

()

   * Closes the current reader and opens the next one, if any.
   */
  private void advance() throws IOException {
    close();
    if (it.hasNext()) {
      current = it.next().openStream();
    }
  }

  @Override
  public int read(@Nullable char cbuf[], int off, int len) throws IOException {