* @deprecated Prefer {@code asCharSource(file, charset).readFirstLine()}.
   */
  @Deprecated
  @InlineMe(
      replacement = "Files.asCharSource(file, charset).readFirstLine()",
      imports = "com.google.common.io.Files")
  public
  static @Nullable String readFirstLine(File file, Charset charset) throws IOException {
    return asCharSource(file, charset).readFirstLine();
  }

  /**

   * it does.
   *
   * @throws IOException if an I/O error occurs while reading from this source
   */
  public @Nullable String readFirstLine() throws IOException {
    Closer closer = Closer.create();
    try {
      BufferedReader reader = closer.register(openBufferedStream());
      return reader.readLine();
    } catch (Throwable e) {

    assertExpectedString(string);
  }

  public void testReadFirstLine() throws IOException {
    if (expectedLines.isEmpty()) {
      assertThat(source.readFirstLine()).isNull();
    } else {
      assertThat(source.readFirstLine()).isEqualTo(expectedLines.get(0));
    }
  }

  public void testReadLines_toList() throws IOException {
    assertExpectedLines(source.readLines());
  }

    File temp = createTempFile();
    assertThat(Files.readFirstLine(temp, UTF_8)).isNull();
    assertTrue(Files.readLines(temp, UTF_8).isEmpty());

    PrintWriter w = new PrintWriter(Files.newWriter(temp, UTF_8));
    w.println("hello");
    w.println("");
    w.println(" world  ");
    w.println("");
    w.close();

    assertThat(Files.readFirstLine(temp, UTF_8)).isEqualTo("hello");

    assertTrue(source.wasStreamOpened() && source.wasStreamClosed());
  }

  public void testReadFirstLine() throws IOException {
    TestCharSource lines = new TestCharSource(LINES);
    assertThat(lines.readFirstLine()).isEqualTo("foo");
    assertTrue(lines.wasStreamOpened() && lines.wasStreamClosed());
  }

  public void testReadLines_toList() throws IOException {
    TestCharSource lines = new TestCharSource(LINES);