java - Server-client file transfer null pointer exception -


i'm developing server client file transfer program on java, , couldn't figure out how fix following code don't know socket programming. code client side's codes:

string receiverip = null;     int serverport = 0;     hostip = args[0];     serverport = integer.parseint(args[1]);     string filetosend = args[2];      byte[] abyte = new byte[1];     int bytesr;     socket clientsocket = null;     socket connectsocket = null;     bufferedoutputstream toclient = null;     inputstream = null;      try {         toclient = new bufferedoutputstream(connectsocket.getoutputstream());         clientsocket = new socket(hostip, serverport);         = clientsocket.getinputstream();     } catch (ioexception ex) {         system.out.println(ex);     }

as problem, null pointer exception on line 14 (undoubtedly since connectsocket null), have no idea can assign on connectsocket(if on server side connection accept socket could've been assigned begin writing after connecion established.)

contrary seem believe, not need 2 separate sockets read , write server. 1 socket suffice. can call getinputstream method stream read server, , getoutputstream stream write server. don't need 2 sockets, one.


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