How to set default download directory in selenium Chrome Capabilities?

Please find the below code with the chrome capabilities. In fact the browser is not downloading the file to the specified path.

private static DesiredCapabilities getChromeCapabilities() throws Exception {

    String chromePath = BrowserUtil.class.getResource("/Browserdrivers/chromedriver.exe").getPath();
    System.setProperty("webdriver.chrome.driver", chromePath);
    String downloadFilepath = "C:\\TestDownloads";
    ChromeOptions options = new ChromeOptions();
    HashMap<String, Object> chromePrefs = new HashMap<String, Object>();
    chromePrefs.put("profile.default_content_settings.popups", 0);
    chromePrefs.put("download.default_directory", downloadFilepath);
    options.setExperimentalOption("prefs", chromePrefs);
    options.addArguments("--test-type");
    options.addArguments("start-maximized", "disable-popup-blocking");

    DesiredCapabilities chromeCapabilities = DesiredCapabilities.chrome();
    setProxy(chromeCapabilities);
    chromeCapabilities.setPlatform(Platform.WINDOWS);
    chromeCapabilities.setCapability("name", MDC.get("testname"));
    chromeCapabilities.setCapability(ChromeOptions.CAPABILITY, options);
    return chromeCapabilities;
}

For Chromedriver try out with :

String downloadFilepath = "/path/to/download";
HashMap<String, Object> chromePrefs = new HashMap<String, Object>();
chromePrefs.put("profile.default_content_settings.popups", 0);
chromePrefs.put("download.default_directory", downloadFilepath);
ChromeOptions options = new ChromeOptions();
options.setExperimentalOption("prefs", chromePrefs);
DesiredCapabilities cap = DesiredCapabilities.chrome();
cap.setCapability(CapabilityType.ACCEPT_SSL_CERTS, true);
cap.setCapability(ChromeOptions.CAPABILITY, options);
WebDriver driver = new ChromeDriver(cap);

Note:- Use File.separator to handle slashes, it will put syntax as per os it is executing the code. In windows you need to use \\ for path while if you are using linux or mac then use //

Hope this helps. :)