Null pointer Exception on Parsing URL in android

Question

Here Im trying to parsing read from url and trying to print in console.Im using Asynctask as we cant have network connection on main thread

package com.example.parse;

import java.io.BufferedReader;
import java.io.IOException; 
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;

import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final Button create =(Button) findViewById(R.id.button1);
    create.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            // Perform action on click

            EditText et1 = (EditText) findViewById(R.id.editText1);
            String url = et1.getText().toString();
            new ParseString().execute(url);

        }
    });
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

}

  class ParseString extends AsyncTask<String, Void, BufferedReader>{

@Override
protected BufferedReader doInBackground(String... urls) {
    // TODO Auto-generated method stub

    BufferedReader in = null;
    URL url = null;
    try {
        url = new URL(urls[0]);
    } catch (MalformedURLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    try {
            in = new BufferedReader(
                new InputStreamReader(
                url.openStream()));
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    return in;
}

protected void onPostExecute(BufferedReader buf){

    String inputLine;

    try {
        while ((inputLine = buf.readLine()) != null)
            System.out.println(inputLine);
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    try {
        buf.close();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }


}
}

This is the log cat error message

12-13 01:33:58.404: E/AndroidRuntime(1058): FATAL EXCEPTION: AsyncTask #2
12-13 01:33:58.404: E/AndroidRuntime(1058): Process: com.example.parse, PID: 1058
12-13 01:33:58.404: E/AndroidRuntime(1058): java.lang.RuntimeException: An error occured while executing     doInBackground()
12-13 01:33:58.404: E/AndroidRuntime(1058):     at android.os.AsyncTask$3.done(AsyncTask.java:300)
12-13 01:33:58.404: E/AndroidRuntime(1058):     at     java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
12-13 01:33:58.404: E/AndroidRuntime(1058):     at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
12-13 01:33:58.404: E/AndroidRuntime(1058):     at java.util.concurrent.FutureTask.run(FutureTask.java:242)
12-13 01:33:58.404: E/AndroidRuntime(1058):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
12-13 01:33:58.404: E/AndroidRuntime(1058):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
12-13 01:33:58.404: E/AndroidRuntime(1058):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
12-13 01:33:58.404: E/AndroidRuntime(1058):     at java.lang.Thread.run(Thread.java:841)
12-13 01:33:58.404: E/AndroidRuntime(1058): Caused by: java.lang.NullPointerException
12-13 01:33:58.404: E/AndroidRuntime(1058):     at com.example.parse.ParseString.doInBackground(MainActivity.java:62)
12-13 01:33:58.404: E/AndroidRuntime(1058):     at com.example.parse.ParseString.doInBackground(MainActivity.java:1)
12-13 01:33:58.404: E/AndroidRuntime(1058):     at android.os.AsyncTask$2.call(AsyncTask.java:288)
12-13 01:33:58.404: E/AndroidRuntime(1058):     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
12-13 01:33:58.404: E/AndroidRuntime(1058):     ... 4 more

P.S I have added network permission in manifest.xml

when you `catch (MalformedURLException e)` you should immediately return null. Otherwise, you proceed and try to call url.openStream(), while url might be null due to previously ignored `MalformedURLException` — kiruwka, Dec 13 '13 at 10:46
The prob is when ever i give a url im getting runtime execution its not evn working once — Abhishek, Dec 13 '13 at 10:49
@kiruwka evn aftr returning null in catch block its showing same exception — Abhishek, Dec 13 '13 at 10:51
then just add : `if (url == null) { return null; } ` before your code with `openStream` — kiruwka, Dec 13 '13 at 10:59
@dipali THanks for the answer it was helpful and i got another solution as well http://stackoverflow.com/questions/17271147/android-get-content-from-url — Abhishek, Dec 15 '13 at 07:11

score 0 · Answer 1 · answered Dec 13 '13 at 10:59

Use this in your asynctask :-

import java.net.*;
public class DemoConvertURItoURL {

    public static void main(String[] args) {
        URI uri = null;
        URL url = null;
        String uriString = "http://www.google.co.in/"; // In your case "urls[0]" 
        //without the quotes

        // Create a URI object
        try {
            uri = new URI(uriString);
        } catch (URISyntaxException e) {
            e.printStackTrace();
        }

        // Convert the absolute URI to a URL object
        try {
            url = uri.toURL();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
         // Write your BufferedReader code here
        //print the URI and URL 
        System.out.println("Original URI  : " + uri);
        System.out.println("Converted URL : " + url);

    }

}

score 0 · Accepted Answer · answered Dec 13 '13 at 11:25

class testsTask extends AsyncTask<String, Integer, Integer> {


            @Override
            protected void onPreExecute() 
            {
                h=new Handler();

                pd = ProgressDialog.show(ctx, "", "Please Wait.");
                pd.setCancelable(false);
                pd.setCanceledOnTouchOutside(false);
            }

            String response;


            protected Integer doInBackground(String... urls) {
                int webresponse=-1;
                try {
                    response = httpClient.SendHttpPost(urls[0].toString(), jsonObjAuth);
                    if (response.equalsIgnoreCase("")) {
                        webresponse= 1;
                    } else {
                        webresponse= 0;
                    }
                } catch (IOException e) {


                    e.printStackTrace();
                }
                return webresponse;
            }

            protected void onPostExecute(Integer result) 
            {
                if (result == 0) 
                {

                    strResponse = response;
                    Log.i("resp", strResponse);

                    pd.dismiss();

                }
            }
        }

I hope its useful to you....

it was useful and i even got another solution http://stackoverflow.com/questions/17271147/android-get-content-from-url — Abhishek, Dec 15 '13 at 07:13

score 0 · Answer 3 · answered Dec 13 '13 at 13:11

first check internet permission in android menifest file

and then

try this

URL url = null;
    try {
        url = new URL(url);//u use urls[0]
    } catch (MalformedURLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

Null pointer Exception on Parsing URL in android

3 Answers3