Q:

Unable to click a href link using Selenium

I have an HTML href link
<a class="btn btn-icon-text btn-secondary" data-toggle="modal" data-target="#recordSharingDownloadModal" href="/person/mL7CD8tR59g2Cy2/health-record/sharing/media/clinical-summary/%7B7c-06-74-be-dc-67-47-5d-be-92-4c-58-5a-fd-1b-8f%7D/download-options/" title="Download Document">Download</a>

using Selenium I need to click the link. Currently, I am using below code -
driver.findElement(By.xpath("//a[contains(@href='/person/mL7CD8tR59g2Cy2/health-record/sharing/media/clinical-summary/%7B7c-06-74-be-dc-67-47-5d-be-92-4c-58-5a-fd-1b-8f%7D/download-options/')]")).click();

But it is throwing an error 

"java.lang.NullPointerException"

I have also tried to click the button using CssSelector but still the same error. I need to click a Download button under clinical summary section but there are multiple sections with the same button name. Only the HREF is unique.
Can anyone please help me?
The piece of code:
package LaunchIQHealth;

import java.io.File;
import java.io.IOException;
import org.apache.commons.io.FileUtils;
import org.openqa.selenium.By;
import org.openqa.selenium.JavascriptExecutor;
import org.openqa.selenium.OutputType;
import org.openqa.selenium.TakesScreenshot;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.support.ui.*;

public class AutomateIQHealth 
{
    public static void main(String[] args) throws IOException, InterruptedException
    {
        System.setProperty("webdriver.chrome.driver", "C:\\Users\\abc\\Desktop\\chromedriver.exe");
        WebDriver driver = new ChromeDriver();
        WebDriverWait wait = new WebDriverWait(driver, 20);
            driver.get("url");
            ((JavascriptExecutor)driver).executeScript("scroll(0,400)").equals("Clinical Summaries");  
            wait.until(ExpectedConditions.visibilityOfElementLocated(By.xpath("//*[contains(text(), 'Download")));      
            driver.findElements(By.xpath("//a[@href='/person/mL7CD8tR59g2Cy2/health-record/sharing/media/clinical-summary/%7B7c-06-74-be-dc-67-47-5d-be-92-4c-58-5a-fd-1b-8f%7D/download-options/']")).get(0).click();
    }
}

A:

If I consider your current pasted code as the exact one, you won't be able to do either:
driver.findElement(By.xpath("//a[contains(@href='/person/mL7CD8tR59g2Cy2/health-record/sharing/media/clinical-summary/%7B7c-06-74-be-dc-67-47-5d-be-92-4c-58-5a-fd-1b-8f%7D/download-options/')]")).click();

or

driver.findElements(By.xpath("//a[@href='/person/mL7CD8tR59g2Cy2/health-record/sharing/media/clinical-summary/%7B7c-06-74-be-dc-67-47-5d-be-92-4c-58-5a-fd-1b-8f%7D/download-options/']")).get(0).click();

The reason is, chromedriver happily opens the Chrome Browser for you but as you have tried to executeScript("scroll(0,400)").equals("Clinical Summaries"); but as per the documentation JavascriptExecutor which is an Interface and the associated methods executeScript and executeAsyncScript can't invoke click() method.

