url.openStream() gives NullPointerException for just one url

Question

please do not mark it as a duplicated because I have already searched Stackoverflow before posting it, and found this solution,

url.openstream() or urlconnection.getinputstream() raise nullpointerexception on valid URL

but this solution doesn't work either.

The problem is i am trying to openStream on this url > http://www.techworld.com/security/rss for my Android App.

but it always give NullPointerException.

I first checked the connection to see if the connection is successful,

connection.getResponseCode();

and it return 200 so the connection is ok.

Then according to the available solutions, I changed the JRE version from 1.7 to 1.6 but this still don't work.

When I try to openStream other urls then they work absolutely fine with the same code but the above link gives NPE.

this is the code,

URL mylink = new URL ("http://www.techworld.com/security/rss");

HttpURLConnection connection;
connection = (HttpURLConnection) myLink.openConnection();   
connection.connect();

if (connection.getResponseCode() == HttpURLConnection.HTTP_OK) {
    try {
        domObject = new DOM(myLink.openStream());
        domObject.start();

    } catch (Exception e) {
        Log.e(TAG,e+" " + host);
    }    
}

in the above code, host = myLink.getHost();.

one more thing i would like to mention that, when I run this code as a Java project instead of Android project then it loads finds and do not throw NPE.

What could be the problem here ?

This is the logCat, it only shows one line error,

01-21 20:46:11.575: E/testApp(30335): java.lang.NullPointerException www.techworld.com

Show the stack trace of the NPE? From the snippet above, the only logical NPE comes from the `connection.connect()` line — Kon, Jan 21 '15 at 16:00
no , it shows `NPE` on `openStream` line, as you can see the `catch` block of the updated code. I have also added Logcat , please see. I would also like to mention that other URLs load absolutely fine. — bhuvesh, Jan 21 '15 at 16:03
It would actually be more useful if you didn't catch the error in the catch block in this case so that we had a full LogCat stacktrace to look at. So that we know whether it specifically targets lets say the myLink.openStream() or the .start() in the following line. But we will assume you are telling us the connect() line is the culprit. — Jay Snayder, Jan 21 '15 at 16:08
@JaySnayder, actually i tried that but Eclipse gives error that `Unhadled exception type IOException.` — bhuvesh, Jan 21 '15 at 16:09
then use e.printStackTrace() instead custom Log.d ... (inside catch) — Selvin, Jan 21 '15 at 16:10
@bhuvesh Thats good. That provides us with better information on the stacktrace that gets printed out in Logcat. — Jay Snayder, Jan 21 '15 at 16:11

score 2 · Accepted Answer · edited Jul 09 '18 at 10:29

At least this code worked:

URL url;
try {
    url = new URL("http://www.techworld.com/security/rss");
    HttpURLConnection httpURLConnection;
    httpURLConnection = (HttpURLConnection) url.openConnection();
    httpURLConnection.connect();
    if (httpURLConnection.getResponseCode() == HttpURLConnection.HTTP_OK) {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream()));
        StringBuffer stringBuffer = new StringBuffer();
        try {
            String inputLine;
            while ((inputLine = bufferedReader.readLine()) != null) {
                stringBuffer.append(inputLine).append("\n");
            }
        } finally {
            bufferedReader.close();
        }

        System.out.println(stringBuffer.toString());
        }
} catch (IOException e) {
    e.printStackTrace();
}

I think your code tries to open connection twice. While the first connection is not closed, you try connect another myLink.openStream(). It may be better just using connection.getInputStream().

url.openStream() gives NullPointerException for just one url

1 Answers1