@Java/Android Socket failed to read message -

i have trouble java sockets.

i need connect server , client through local network , there can more 2 devices connected router client must find out address of server.

the way know solve problem 3 first numbers of clients ip(v4)-address , loop every of 254 other possible ips. (i know way slow , may cause many problems. if know alternative, glad).

actually client android smartphone can dhcp-info.

the problem is, read command check if device server last forever.

if need code, here is!
code:
oncreate:

    final wifimanager manager = (wifimanager) super.getsystemservice(wifi_service);     final dhcpinfo dhcp = manager.getdhcpinfo();     final string address = inttoip(dhcp.ipaddress);     string addresspart=address.substring(0, address.lastindexof('.')+1);     arraylist<hashmap<string, string>> l = null;     log.d("keyboard","initiating search");     try {         l = new checkconnections().execute(addresspart).get();     } catch (interruptedexception e1) {         e1.printstacktrace();     } catch (executionexception e1) {         e1.printstacktrace();     }     

checkconnections:

    arraylist<hashmap<string,string>> l=new arraylist<hashmap<string,string>>();         for(int i=1;i<=255;i++){         try {             worksocket=new socket(addresspart[0]+i,61927);             workout=new bufferedoutputstream(worksocket.getoutputstream());             workin=new bufferedinputstream(worksocket.getinputstream());             byte[] buffer=new byte[6];             workin.read(buffer);//at point app freezes until stop serverside program             string answer=new string(buffer,"utf-8");             log.i("keyboard","welcome message: "+answer);             if(answer.equalsignorecase("sdk on")){                 hashmap<string,string> hm=new hashmap<string,string>();                 hm.put("address",addresspart[0]+i);                 l.add(hm);                 workout.write(inttobytes(8));                 workout.write("closing".getbytes("utf-8"));                 worksocket.close();                 continue;             }             else{                 log.d("keyboard","no sdk-programm detected");                 worksocket.close();                 continue;             }         } catch (unknownhostexception e) {             log.d("keyboard",addresspart[0]+i+" doesn't exists");             continue;         } catch ( interruptedioexception e){             log.w("system.warn",e.getcause()+e.getlocalizedmessage());             log.d("keyboard","timeout");             continue;         } catch (ioexception e) {             log.d("keyboard",addresspart[0]+i+" doesn't exists");             e.printstacktrace();             continue;         }         }         return l;    

the server's code:

    serversocket serversocket = new serversocket(61927);         system.out.println("socket initiated");         socket client = serversocket.accept();         bufferedinputstream in=new bufferedinputstream(client.getinputstream());         bufferedoutputstream out=new bufferedoutputstream(client.getoutputstream());         system.out.println("client found");         byte[] buffer=new byte[11];         out.write("sdk on".getbytes("utf-8"));         in.read(buffer);         string s=new string(buffer,"utf-8");         if(!s.equals("got info")){             system.out.println("no sdk client");             client.close();             serversocket.close();             new main();     } 

uh, think should ping broadcast-ip , listen answers instead...
android's linux runtime allows read ip answer coming.