Program to check for broken links on a webpage

LinkCheck.java

import java.net.*;
import org.htmlparser.beans.LinkBean;
import org.htmlparser.http.HttpHeader;
import java.util.*;
import java.io.*;


public class LinkCheck
{

    public static URL[] getLinks(String url)
    {
        // Use LinkBean class from HTMLParser to get array of links from a page
        LinkBean lb = new LinkBean ();
        lb.setURL (url);
        URL[] urls = lb.getLinks ();
        return urls;
    }
    
    public static boolean isImage(URL url)
    {
        String urlString = url.toString();
        
        // Get the last three chars of url
        int last = urlString.length()-1;
        int extStart = urlString.length()-3; 
        String ext = urlString.substring(extStart);
        
        // If these match standard image formats, it's an image
        if (ext.equalsIgnoreCase("jpg")||ext.equalsIgnoreCase("png")||ext.equalsIgnoreCase("gif")||ext.equalsIgnoreCase("tif"))
            return true;
        // Otherwise, it's not
        else 
            return false;
    
    }
    
    public static boolean isNotGoogle(URL url)
    {
        String urlString = url.toString();
        if (urlString.contains("google"))
            return false;
        else 
            return true;
    
    }

    public static void main (String[] args)
    {
       try
       {
       
            // Use getLinks to return array of links from website specified at command-line
            URL[] urls = getLinks(args[0]);

            // Create an array of same size to store Response Codes
            int[] codes = new int[urls.length];
            
            // Create ArrayLists to store info from Broken Links
            ArrayList <URL> brokenLinks = new ArrayList <URL> ();
            ArrayList <Integer> brokenCodes = new ArrayList <Integer> ();
            ArrayList <String> brokenReasons = new ArrayList <String> ();
           
            // Iterate through the Urls
            for (int i = 0; i < urls.length; i++)
            {
                try
                {
                
                    // Connect to the URL and add Response Code to Codes Array
                    HttpURLConnection connect = (HttpURLConnection) urls[i].openConnection();           
                    codes[i] = connect.getResponseCode();                
                
                    // If the link is broken & not a Google link, add its info into ArrayLists
                    if (connect.getResponseCode() != 200 && isNotGoogle(urls[i]))
                    {
                                          
                            brokenLinks.add(urls[i]);
                            brokenCodes.add(codes[i]);                    
                    
                            // If is an image, this is the Reason
                            if (isImage(urls[i]))
                                brokenReasons.add("Is Image - Access not Allowed");
                    
                            // If code is 404, Reason is File not Found
                            else if (codes[i] == 404)
                                brokenReasons.add("File not Found");
                                
                            // If code is 403, Reason is Access Forbidden                       
                            else if (codes[i] == 403)
                                brokenReasons.add("Access Forbidden by server");
                                
                            // If code is 302, Reason is file moved    
                            else if (codes[i] == 302)
                                brokenReasons.add("File temporarily moved");
 
                            //Otherwise reason is unknown
                            else
                            brokenReasons.add("Unknown");                                 
                      }
               
                     connect.disconnect();  
                           
              }
                // If the connection fails catch exception
                catch (Exception e)
                {
                              
                } 
            }
     
              
            // Create String to hold output HTML
            String resultHTML = "<html><title>Broken Links - "+args[0]+"</title><br>"
                + "<h2> Broken Links for "+args[0]+ "</h2> <br><table border=1>"
                + "<tr><td><b>Link</b></td><td><b>Response Code</b></td><td><b>Reason for Failure</b></td></tr>";
             // Iterate through the Array Lists to get the data about Broken Links
             for (int i= 0; i<brokenLinks.size(); i++)
             {  
                resultHTML+= "<tr><td><a href=\"" +brokenLinks.get(i)+ "\">"+brokenLinks.get(i)+"</a></td><td>" 
                +brokenCodes.get(i)+ "</td><td>" +brokenReasons.get(i)+ "</td> </tr>";
                           
             } 
           // Close HTML and create custom-named file for output
            resultHTML += "</html>";
            String filename = args[0].substring(7);
            
            // Replace any forward slashes with hyphens
            filename = filename.replace("/","-");
            filename = "BrokenLinks_" + filename;
            
            FileWriter fstream = new FileWriter(filename);
			BufferedWriter out = new BufferedWriter(fstream);
		    
			out.write(resultHTML);
			out.close(); 
			
                 
        }
        catch (Exception e)
        {
           String s = e.getMessage();
           if (s != null) 
           {
               System.out.println(s);
           }
          
        }

    }
}