This code downloads a file on the BrowserStack machine and uploads the same to verify if the file was downloaded successfully or not

Verify_Downloaded_File.java

import java.io.File;
import java.io.FileReader;
import java.net.URL;

import org.apache.commons.io.FileUtils;
import org.openqa.selenium.By;
import org.openqa.selenium.OutputType;
import org.openqa.selenium.TakesScreenshot;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.remote.DesiredCapabilities;
import org.openqa.selenium.remote.RemoteWebDriver;

public class Verify_Downloaded_File {

	public static void main(String[] args) {

    // VALIDATE YOUR BROWSERSTACK ACCOUNT DETAILS HERE - https://www.browserstack.com/accounts/settings
		String USERNAME = "<BROWSERSTACK_USERNAME>";
		String AUTOMATE_KEY = "BROWSERSTACK_ACCESS_KEY";
		String HUB_URL = "https://" + USERNAME + ":" + AUTOMATE_KEY + "@hub-cloud.browserstack.com/wd/hub";
		
		String AUT_URL = "https://the-internet.herokuapp.com/download";
		String file_name = null;
		String file_path = null;
		
		URL URLObj = null;
		WebDriver webDriver = null;
		WebElement webElement = null;
		DesiredCapabilities caps = null;

		try {

			URLObj = new URL(HUB_URL);
			caps = new DesiredCapabilities();
		
			caps.setCapability("os", "Windows");
			caps.setCapability("os_version", "10");
			caps.setCapability("browserName", "Chrome");
			caps.setCapability("browser_version", "69.0");
			
			caps.setCapability("project", "Test Run");
			caps.setCapability("build", "Automate Feature");
			caps.setCapability("name", "Test: Upload the newly downloaded file");
			
			caps.setCapability("browserstack.console", "verbose");
			caps.setCapability("browserstack.debug", "true");
			
			webDriver = new RemoteWebDriver(URLObj, caps);
			webDriver.get(AUT_URL);
			webDriver.manage().window().maximize();
			Thread.sleep(7000);
			
			// CODE TO ENSURE ONLY A NON-EXE FILE IS DOWNLOADED
			webElement = webDriver.findElement(By.xpath(".//div[@class='example']/a[1]"));
			if(webElement.getText().contains(".exe")){
				webElement = webDriver.findElement(By.xpath(".//div[@class='example']/a[2]"));
				if(webElement.getText().contains(".exe")){
					webElement = webDriver.findElement(By.xpath(".//div[@class='example']/a[3]"));
					if(webElement.getText().contains(".exe")){
						webElement = webDriver.findElement(By.xpath(".//div[@class='example']/a[4]"));
						if(webElement.getText().contains(".exe")){
							webElement = webDriver.findElement(By.xpath(".//div[@class='example']/a[5]"));
						}
					}
				}
			}
			
			file_name = webElement.getText().trim();
			
			// FOR WINDOWS 10/8.1/8/7
			file_path = "C:\\Users\\hello\\Downloads\\" + file_name;
			System.out.println("#" + file_path + "#");
		
			// FOR WINDOWS XP
			// file_path = "C:\\Documents and Settings\\hello\\Downloads\\" + file_name;

			// FOR OS X
			// file_path = "/Users/test1/Downloads/" + file_name);
			
			webElement.click();
			Thread.sleep(10000);
			
			take_screenshot(webDriver);
			
			AUT_URL = "https://the-internet.herokuapp.com/upload";
			webDriver.get(AUT_URL);
			
			Thread.sleep(5000);
			
			webDriver.findElement(By.xpath(".//input[@id='file-upload']")).sendKeys(file_path);
			webDriver.findElement(By.xpath(".//input[@id='file-submit']")).click();

			Thread.sleep(4000);
			take_screenshot(webDriver);

			
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if(webDriver != null){
				webDriver.quit();
			}
		} 
	} // MAIN END
	
	public static void take_screenshot(WebDriver webDriver){
		try {
			TakesScreenshot scrShot =((TakesScreenshot)webDriver);
			File SrcFile=scrShot.getScreenshotAs(OutputType.FILE);
//			File DestFile=new File("/Users/test.png");
//			FileUtils.copyFile(SrcFile, DestFile);
		} catch (Exception e) {
			 e.printStackTrace();
		}
	} // FUNC END
} // CLASS END