android - java.lang.NullPointerException in Handler on dispatchMessage -

i'm new in android programming , have sporadic error in handler service. log error is:

java.lang.nullpointerexception @ com.rafag.taxialerta.radartaxiservice$buzonmensajetareaubicaciones.handlemessage(radartaxiservice.java:105) @ android.os.handler.dispatchmessage(handler.java:106) @ android.os.looper.loop(looper.java:136) @ android.app.activitythread.main(activitythread.java:5212) @ java.lang.reflect.method.invokenative(native method) @ java.lang.reflect.method.invoke(method.java:515) @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:786) @ com.android.internal.os.zygoteinit.main(zygoteinit.java:602) @ dalvik.system.nativestart.main(native method) 

my code is:

private handler puentetareaubicaciones;     static class buzonmensajetareaubicaciones extends handler {         private final weakreference<radartaxiservice> wr;         buzonmensajetareaubicaciones(radartaxiservice srv) {             wr = new weakreference<>(srv);         }         @override         public void handlemessage(message msg) {             radartaxiservice srv = wr.get();             if (srv == null){                 super.handlemessage(msg);                 return ;             }             message nuevomsg = message.obtain();             switch (msg.what) {                 case puente_ok:                     srv.recibosituacion(msg.what);                     nuevomsg.what = msg.what;                     try {                         srv.buzonmapa.send(nuevomsg);                     } catch (remoteexception e) {                         e.printstacktrace();                     }                     break;                 default:                     super.handlemessage(msg);                     break;             }         }     } 

line 105 is:

srv.buzonmapa.send(nuevomsg) 

buzonmapa init @ onbind service:

public ibinder onbind(intent intent) {     return buzonservicio.getbinder(); } 

and:

static class buzonmensajemapa extends handler {     private final weakreference<radartaxiservice> wr;      buzonmensajemapa(radartaxiservice srv) {         wr = new weakreference<>(srv);     }      @override     public void handlemessage(message msg) {         radartaxiservice srv = wr.get();         if (srv == null) {             super.handlemessage(msg);             return;         }         srv.buzonmapa = msg.replyto;         srv.misituaciones(msg.what);     } } 

in main activity, onserviceconnected:

public void onserviceconnected(componentname name, ibinder service) {     buzonservicio = new messenger(service);     try {         message msg = message.obtain();         msg.replyto = buzonactividad;         buzonservicio.send(msg);     } catch (remoteexception e) {         //e.printstacktrace();     } } 

i have error 1 of hundred times, not able find patron reproduce always.

the general flow is:

activity ----------------> service --------------------> thread         buzonmapa<------------+  puentetareaubicaciones<---+  

any ideas?

it weakreference. cannot sure srv not null or gce'd. check whether srv not null.