@SuppressWarnings("unchecked")
@Test
public void testDefaultSelectedCheckbox() { 
    
    WebDriver driver = new ChromeDriver();
    driver.get("http://dl.dropbox.com/u/55228056/Locators.html");
    
    //Expected list of selected Checkbox
    List<String> checked =  Arrays.asList(new String[]{"user1_admin", "user3_browser"});
    
    //Create an instance of JavaScript Executor from driver
    JavascriptExecutor js = (JavascriptExecutor) driver;

    //Locate all the Checkbox which are checked by calling jQuery //find() method. 
    //find() method returns elements in array
    List<WebElement> elements = (List<WebElement>) js.executeScript("return jQuery.find(':checked')");

    //Verify two Checkbox are selected 
    assertEquals(elements.size(),2);

    //Verify correct Checkbox are selected
    for (WebElement element : elements)
        assertTrue(checked.contains(element.getAttribute("id")));
    
    driver.close();
}

//Locate all the Checkbox which are checked by calling jQuery find() method. 
//find() method returns elements in array
List<WebElement> elements = (List<WebElement>) js.executeScript("return jQuery.find(':checked')");

private void injectjQueryIfNeeded() {
    if (!jQueryLoaded())
        injectjQuery();
}

public Boolean jQueryLoaded() {
    Boolean loaded;
    try {
        loaded = (Boolean) driver.executeScript("return jQuery()!=null");
    } catch (WebDriverException e) {
        loaded = false;
    }
    return loaded;
}

public void injectjQuery() {
    driver.executeScript(" var headID = document.getElementsByTagName(\"head\")[0];"
    + "var newScript = document.createElement('script');"
    + "newScript.type = 'text/javascript';"
    + "newScript.src = 'http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js';"
    + "headID.appendChild(newScript);");
}