android - Excute URL get, Error when executing urlget

I want to excute a simple url get, I used the code inside this link
http://developer.android.com/reference/java/net/HttpURLConnection.html

I want to run this code inside a click event:

 URL url = new URL("http://www.android.com/");
   HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
   try {
     InputStream in = new BufferedInputStream(urlConnection.getInputStream());
     readStream(in);}
    finally {
     urlConnection.disconnect();
   }

When I run the app I am getting this long error:

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.soma.smsserver1, PID: 20664
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:289)
at android.view.View.performClick(View.java:5198)
at android.view.View$PerformClick.run(View.java:21147)

at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284)

at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: android.os.NetworkOnMainThreadException

at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1273)
at java.net.InetAddress.lookupHostByName(InetAddress.java:431)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
at java.net.InetAddress.getAllByName(InetAddress.java:215)
at com.android.okhttp.internal.Network$1.resolveInetAddresses(Network.java:29)
at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:188)
at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:157)
at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:100)
at com.android.okhttp.internal.http.HttpEngine.createNextConnection(HttpEngine.java:357)
at com.android.okhttp.internal.http.HttpEngine.nextConnection(HttpEngine.java:340)

at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:330)
at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:248)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:433)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:384)
at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:231)
at com.example.soma.smsserver1.MainActivity$override.clickMe(MainActivity.java:28)
at com.example.soma.smsserver1.MainActivity$override.access$dispatch(MainActivity.java)
at com.example.soma.smsserver1.MainActivity.clickMe(MainActivity.java:0)
at java.lang.reflect.Method.invoke(Native Method) 
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:284) 

at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

Answer

android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1273)

you cannot process networking on the main thread, this is a security restriction on Android, try wrapping your call in AsyncTask a background service, or thread.

Please read documentation regarding Processes and Threads