java - Android BitmapFactory often returning null on Base64 decoded byte array -

i have java server on pc using infamous robot class capture screenshots, encode them base64 strings , send them android client on socket using printwriter

the android client reads base64 encoded strings, converts them byte arrays , bitmap images display in imageview.

the problem while works expected, bitmapfactory.decodebytearray method return null , hence render nothing imageview.
giving me message in logcat d/skia﹕ --- decoder->decode returned false

i can reproduce successful/unsuccessful decodes changing displayed on pc, can simple highlighting line of onscreen text cause decode starting failing , un-highlighting return succeeding.

when decode has failed have tried both comparing string sent server (is 100% same) , validating base64 encode external tool base64 image converter, shows perfect image.

this happens on both real device running android 4.1 , emulated device on android 5.1

have spent 2 days far poring on , internet in general looking answer haven't found quite fits situation.

why bitmapfactory method failing often? or have stuffed terribly in client code?

android client code

public class mainactivity extends activity {      private socket socket;     private static final int serverport = 6666;     private static final string server_ip = "192.168.2.5";     private imageview imgcontainer;     private bitmap bitmapobj;      @override     public void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);         imgcontainer = (imageview) findviewbyid(r.id.imgcontainer);         new thread(new connectionthread()).start();     }      private class connectionthread implements runnable {          @override         public void run() {              try {                 inetaddress serveraddr = inetaddress.getbyname(server_ip);                  socket = new socket(serveraddr, serverport);                 bufferedreader in = new bufferedreader(new inputstreamreader(socket.getinputstream()));                 // first line garbage                 string instr=in.readline();                 //image receiver loop                 while((instr = in.readline()) != null){                     // log shows string same length 1 sent                     log.d("imgthread", string.valueof(instr.length()));                      byte[] img64 = base64.decode(instr, base64.default);                      //fails here, bitmapfactory decode returns null? not                      bitmapobj = bitmapfactory.decodebytearray(img64, 0, img64.length);                          // update imgcontainer imageview                         mainactivity.this.runonuithread(new runnable() {                             @override                             public void run() {                                  imgcontainer.setimagebitmap(bitmapobj);                             }                         });                  }              } catch (unknownhostexception e1) {                 e1.printstacktrace();             } catch (ioexception e1) {                 e1.printstacktrace();             }          }      } }