public void refresh() throws IOException {
    HostDetails hostDetails = current.get();
    refresh(hostDetails.includesFile, hostDetails.excludesFile);
  }
@Test
  public void testRefreshHostFileReaderWithNonexistentFile() throws Exception {
    FileWriter efw = new FileWriter(excludesFile);
    FileWriter ifw = new FileWriter(includesFile);

    efw.close();

    ifw.close();

    HostsFileReader hfp = new HostsFileReader(includesFile, excludesFile);
    assertTrue(INCLUDES_FILE.delete());
    try {
      hfp.refresh();
      Assert.fail("Should throw NoSuchFileException");
    } catch (NoSuchFileException ex) {
      // Exception as expected
    }
  }