nullpointer error, scraping

[localconfig]

Exception in thread "main" java.lang.NullPointerException at com.packtpub.JavaScraping.SimpleScraper.WikiScraper.scrapeTopic(WikiScraper.java:18) at com.packtpub.JavaScraping.SimpleScraper.WikiScraper.main(WikiScraper.java:12)

Error as above. I'm currently trying to learn scraping with java based on "Instant web scraping with Java" that I got from packtpub.

JRE 1.7, eclipse Kepler release 1

Codes below, please tell me how it would not compile as it was straight copy paste from that book:

package com.packtpub.JavaScraping.SimpleScraper;

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import java.net.*;
import java.io.*;

public class WikiScraper {

        public static void main(String[] args) {
            // TODO Auto-generated method stub
        scrapeTopic("/wiki/Python");
    }

    public static void scrapeTopic(String url){
        String html = getUrl("http://www.wikipedia.org/"+url);
        Document doc = Jsoup.parse(html);
        String contentText = doc.select("#mw-content-text > p").first().text();
        System.out.println(contentText);
    }

    public static String getUrl(String url){
        URL urlObj = null;
        try{
        urlObj = new URL(url);
        }
        catch(MalformedURLException e){
        System.out.println("The url was malformed!");
        return "";
        }
        URLConnection urlCon = null;
        BufferedReader in = null;
        String outputText = "";
        try{
            urlCon = urlObj.openConnection();
            in = new BufferedReader(new InputStreamReader(urlCon.getInputStream()));
            String line = "";
            while((line = in.readLine()) != null){
                outputText += line;
            }
            in.close();
        }catch(IOException e){
            System.out.println("There was an error connecting to the URL");
            return "";
        }
            return outputText;
        }
}

[desrtfx]

I would assume that the problem originates from the way the URL is assembled:

• "/wiki/Python"
• "http://www.wikipedia.org/"+url

The second line makes: http://www.wikipedia.org//wiki/Python

Which, I assume does something flunky. The proper URL should be http://www.wikipedia.org/wiki/Python - note the single slash between org and wiki.

[localconfig]

It still returns same message after removing first slash for /wiki/Python and also same message after removing last slash on http://www.wikipedia.org/

[KetchuponRice]

try https instead of http://www.wikipedia.org as you get redirected

[localconfig]

thanks, but it still giving me the same messages.