java - ServerSocket do not work -

i beginner. run following code.

 import android.app.activity;  import android.os.bundle;  import android.os.networkonmainthreadexception;   import java.io.ioexception;  import java.net.serversocket;  import java.net.socket;   public class mainactivity extends activity {  serversocket server = null;  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);      try {         server = new serversocket(4444);     } catch (ioexception e) {         e.printstacktrace();     }      try {         socket client = server.accept();     } catch (ioexception e) {         e.printstacktrace();     }   } }  

but can see app stopped working message in emulator when run. found error occur on statement socket client = server.accept();. think statement wait until client request accepted. these user permissions added.

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

i using android studio. , sdk 14.

you cant run network on ui thread , , think need while(1) when accept , try :

new thread(new runnable() {  public void run() {    try {          socket client = server.accept();      } catch (ioexception e) {          e.printstacktrace();      }  }  }).start();