Java unknown host exception

Question

I am trying to access textalertapp.com via HTTP Post request from my android application. But I am getting Unknown host error. Can anybody help me solve this issue.

12-13 01:30:16.058: WARN/System.err(473): java.net.UnknownHostException: textalertapp.com
    12-13 01:30:16.088: WARN/System.err(473):     at java.net.InetAddress.lookupHostByName(InetAddress.java:513)
    12-13 01:30:16.088: WARN/System.err(473):     at java.net.InetAddress.getAllByNameImpl(InetAddress.java:278)
    12-13 01:30:16.088: WARN/System.err(473):     at java.net.InetAddress.getAllByName(InetAddress.java:242)
    12-13 01:30:16.088: WARN/System.err(473):     at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:136)
    12-13 01:30:16.099: WARN/System.err(473):     at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
    12-13 01:30:16.099: WARN/System.err(473):     at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
    12-13 01:30:16.099: WARN/System.err(473):     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:348)
    12-13 01:30:16.108: WARN/System.err(473):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
    12-13 01:30:16.118: WARN/System.err(473):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
    12-13 01:30:16.118: WARN/System.err(473):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
    12-13 01:30:16.118: WARN/System.err(473):     at com.textalert.alertCollection.getAlerts(alertCollection.java:46)
    12-13 01:30:16.118: WARN/System.err(473):     at com.textalert.alertsList$1.run(alertsList.java:81)
    12-13 01:30:16.128: WARN/System.err(473):     at java.lang.Thread.run(Thread.java:1096)

Code is

 HttpClient client = new DefaultHttpClient();
                String postURL = "http://textalertapp.com/androidCode/?api=AlertManager&method=getAlerts";
                HttpPost post = new HttpPost(postURL); 

                List<NameValuePair> params = new ArrayList<NameValuePair>();
                params.add(new BasicNameValuePair("user", "kris"));
                params.add(new BasicNameValuePair("pass", "xyz"));
                UrlEncodedFormEntity ent = new UrlEncodedFormEntity(params,HTTP.UTF_8);
                post.setEntity(ent);
                HttpResponse responsePOST = client.execute(post);  
                HttpEntity resEntity = responsePOST.getEntity();  
                if (resEntity != null) {    
                    Log.i("RESPONSE",EntityUtils.toString(resEntity));
                }

Could you provide the source code that causes the exception, please? — Thomas
– Thomas, Commented Dec 13, 2010 at 9:43

Ayaz Alavi · Accepted Answer · 2010-12-13 09:46:56Z

53

<uses-permission android:name="android.permission.INTERNET"></uses-permission>

I just added this line in manifest file. Problem solved

answered Dec 13, 2010 at 9:46

Ayaz Alavi

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3 Comments

AlexR Over a year ago

Cool! This is the case I did not think about.

viv Over a year ago

This is correct, you missed the permissions, will solve your problem...., i have checked with code.......

deadfish Over a year ago

insert this code after <manifest and before <application` it will works. Tried after <application and it fails :)

AlexR · Accepted Answer · 2010-12-13 09:44:50Z

6

This means that your host is unknown, i.e. does not exist or is not accessible. Check you IP again and check whether you can get this IP from your device. Probably this IP exists in your local network and is not accessible from outside.

If IP exists check firewall definitions. Firewall cause the same effect.

answered Dec 13, 2010 at 9:44

AlexR

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1 Comment

BlackHatSamurai Over a year ago

+1 for making sure that there is a connection. With Android devices, we often forget that there needs to be either a wifi connection or other form of connectivity

Chris Lacy · Accepted Answer · 2011-03-29 23:31:03Z

4

I just started receiving the "java.net.UnknownHostException" error when fetching content from a URL that previously worked perfectly.

After going around in circles for a while, I manually deleted my project's /bin folder and cleaned the project in Eclipse (Project -> Clean), which fixed this error.

answered Mar 29, 2011 at 23:31

Chris Lacy

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