public void testNewWriter() throws IOException {
    File temp = createTempFile();
    assertThrows(NullPointerException.class, () -> Files.newWriter(temp, null));

    assertThrows(NullPointerException.class, () -> Files.newWriter(null, Charsets.UTF_8));

    BufferedWriter w = Files.newWriter(temp, Charsets.UTF_8);
    try {
      w.write(I18N);
    } finally {
      w.close();
    }

  public void testNewWriter() throws IOException {
    File temp = createTempFile();
    assertThrows(NullPointerException.class, () -> Files.newWriter(temp, null));

    assertThrows(NullPointerException.class, () -> Files.newWriter(null, Charsets.UTF_8));

    BufferedWriter w = Files.newWriter(temp, Charsets.UTF_8);
    try {
      w.write(I18N);
    } finally {
      w.close();
    }

      assertThrows(IOException.class, () -> okSource.copyTo(new TestCharSink(option)));
      // ensure reader was closed IF it was opened (depends on implementation whether or not it's
      // opened at all if sink.newWriter() throws).
      assertTrue(
          "stream not closed when copying to sink with option: " + option,
          !okSource.wasStreamOpened() || okSource.wasStreamClosed());
    }
  }

      assertThrows(IOException.class, () -> okSource.copyTo(new TestCharSink(option)));
      // ensure reader was closed IF it was opened (depends on implementation whether or not it's
      // opened at all if sink.newWriter() throws).
      assertTrue(
          "stream not closed when copying to sink with option: " + option,
          !okSource.wasStreamOpened() || okSource.wasStreamClosed());
    }
  }

   * @param charset the charset used to encode the output stream; see {@link StandardCharsets} for
   *     helpful predefined constants
   * @return the buffered writer
   */
  public static BufferedWriter newWriter(File file, Charset charset) throws FileNotFoundException {
    checkNotNull(file);
    checkNotNull(charset);
    return new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file), charset));
  }

  /**

     * lying about the fields below on the grounds that we always initialize them just after the
     * constructor -- an example of the kind of lying that our hypothetical bytecode rewriter would
     * already have to deal with, thanks to DI frameworks that perform field and method injection,
     * frameworks like Android that define post-construct hooks like Activity.onCreate, etc.
     */