Find the all pdf's from webiste -error Exception in thread "main" java.lang.NullPointerException

[Santosh Awalekar]

package santosh_05_06_2017;

import java.io.BufferedInputStream;  

import java.io.BufferedOutputStream;  

import java.io.FileOutputStream;  

import java.io.IOException;  

import java.io.InputStream;  

import java.io.OutputStream;  

import java.net.MalformedURLException;  

import java.net.URL;  

//import java.util.ArrayList;  

//import java.util.ArrayList;

import java.util.List;  

import org.openqa.selenium.By;  

import org.openqa.selenium.WebDriver;  

import org.openqa.selenium.WebElement;  

import org.openqa.selenium.chrome.ChromeDriver;

//import org.openqa.selenium.htmlunit.HtmlUnitDriver; 

public class allpdf {

public static void main(String[] args) throws MalformedURLException, IOException {  

// List<WebElement>  uniqurl = new ArrayList();  

  

System.setProperty("webdriver.chrome.driver", "D:\\chromedriver.exe");

WebDriver driver= new ChromeDriver();

   driver.navigate().to("http://google.com/"); 

// get all page urls  

List<WebElement>  pdfurllist = driver.findElements(By.tagName("a"));  

  

for (WebElement elemnet : pdfurllist) {  

String pdfurl = elemnet.getAttribute("href").trim();  

//check pdf url  

if (pdfurl.contains(".pdf")) {  

// check one file download one time  

//if (!(uniqurl.contains(pdfurl))) {  

// uniqurl.add(pdfurl);  

//print file name and download url  

System.out.println(filename(pdfurl) + " ---&gt; " + pdfurl);  

//download file  

URL url = new URL(pdfurl);  

InputStream in = new BufferedInputStream(url.openStream());  

OutputStream out = new BufferedOutputStream(new FileOutputStream(filename(pdfurl)));  

  

for (int i; (i = in.read()) != -1;) {  

out.write(i);  

}  

in.close();  

out.close();  

            

 }  

 }  

}  

  

// close driver   

 

  

  

  

  // get file name. It depend on download url pattent.  

  private static String filename(String url) 

  {  

    String filename = "";  

    String file[];  

  

    file = url.split("\\/");  

    if (file[file.length - 1].contains("-")) 

    {  

      filename = file[file.length - 1].trim().replace("-", " ");  

    }

    else if (file[file.length - 1].contains("%20")) {  

      filename = file[file.length - 1].trim().replace("%20", " ");  

    }

    else

    {  

      filename = file[file.length - 1].trim();  

    }  

  

    return filename;  

  }  

  

 

}

[thi...@thoughtworks.com]

Which line of code is throwing null pointer exception?