java - Android call recorder application -

i have developed basic call recorder application, working fine on devices versions below 'lollipop', when have run lollipop devices (android 5.0) i'm getting error.

e/mediarecorder(29786): start failed: -2147483648 java.lang.runtimeexception: start failed. @ android.media.mediarecorder.start(native method) @ com.androiddoc.callrecorder_anirbanjana.callrecordingservice.startrec(callrecordingservice.java:234) @ com.androiddoc.callrecorder_anirbanjana.callrecordingservice.oncreate(callrecordingservice.java:54) @ android.app.activitythread.handlecreateservice(activitythread.java:2763) @ android.app.activitythread.access$1800(activitythread.java:148) @ android.app.activitythread$h.handlemessage(activitythread.java:1375) @ android.os.handler.dispatchmessage(handler.java:102) @ android.os.looper.loop(looper.java:135) @ android.app.activitythread.main(activitythread.java:5312) @ java.lang.reflect.method.invoke(native method) @ java.lang.reflect.method.invoke(method.java:372) @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:901) @ com.android.internal.os.zygoteinit.main(zygoteinit.java:696) 

my code below. when call recorder.prepare(); , recorder.start(); i'm getting above error , can't work out why. can advise?

public class callrecordingservice extends service {      mediarecorder myrec = new mediarecorder();     boolean isrecmode = false;      private static final int recorder_samplerate = 8000;     private static final int recorder_channels = audioformat.channel_in_mono;     private static final int recorder_audio_encoding = audioformat.encoding_pcm_16bit;     private audiorecord recorder = null;     private thread recordingthread = null;     private boolean isrecording = false;      int buffersize = audiorecord.getminbuffersize(recorder_samplerate,             recorder_channels, recorder_audio_encoding);      @override     public ibinder onbind(intent arg0) {         return null;     }      public int onstartcommand(intent intent, int flags, int startid) {         return start_sticky_compatibility;     }      @override     public void oncreate() {         // start recording          startrec();           system.out.println("buffer size value " + buffersize);         super.oncreate();     }      public void stoprec() {         myrec.reset();         toast.maketext(callrecordingservice.this, "rec stoped",                 toast.length_short).show();         log.i("callrecordingservice", "rec stoped");         isrecmode = false;     }       public void startrec() {         try {             // string selectedpath = this.getapplicationcontext().getfilesdir()             // + "/system_sound";             string selectedpath = environment.getexternalstoragedirectory()                     + "/testing";              simpledateformat sdf = new simpledateformat(                     "dd_mm_yyyy_hh_mm_ss aa");             string currentdateandtime = sdf.format(new date());              // crate folder if not exist             // string packagename = this.getpackagename();             file yourdir = new file(environment.getexternalstoragedirectory()                     + "/testing");             // file yourdir = new             // file(this.getapplicationcontext().getfilesdir() +             // "/system_sound");             if (!yourdir.exists()) {                 yourdir.mkdirs();             }             // string selectedpath =             // environment.getexternalstoragedirectory().getabsolutepath() +             // "/android/data/" + packagename + "/system_sound";              myrec.setaudiosource(mediarecorder.audiosource.voice_call);             myrec.setoutputformat(mediarecorder.outputformat.three_gpp);             myrec.setaudioencoder(mediarecorder.audioencoder.amr_nb);             // myrec.setoutputfile(environment.getexternalstoragedirectory().getpath()+"/my_rec_voice.mp3");             myrec.setoutputfile(selectedpath + "/" + currentdateandtime + "_"                     + getfrompreference("phoneno") + ".amr");              audiomanager am; // audio manager              = (audiomanager) getsystemservice(context.audio_service);             am.setmode(audiomanager.mode_in_call);             int volume_level =                     .getstreamvolume(audiomanager.stream_voice_call);             int max_volume =                     .getstreammaxvolume(audiomanager.stream_voice_call);             if (volume_level < max_volume) {                 am.setstreamvolume(audiomanager.stream_voice_call, max_volume,                         audiomanager.flag_show_ui);             }         } catch (illegalstateexception e) {             // log.e("call recorder illegalstateexception: ", "");             terminateanderasefile();         } catch (exception e) {             // log.e("call recorder exception: ", "");             terminateanderasefile();         }          onerrorlistener errorlistener = new onerrorlistener() {              public void onerror(mediarecorder arg0, int arg1, int arg2) {                 terminateanderasefile();             }          };         myrec.setonerrorlistener(errorlistener);          try {             log.v("call recorder", "media recorder prepared");             myrec.prepare();         } catch (illegalstateexception e) {             e.printstacktrace();         } catch (ioexception e) {             e.printstacktrace();         }         try {             log.v("call recorder", "media recorder started ");             myrec.start();          } catch (exception e) {             e.printstacktrace();         }          toast.maketext(callrecordingservice.this, "rec start",                 toast.length_short).show();         log.i("callrecordingservice", "rec start");         isrecmode = true;     }      @override     public void ondestroy() {          stoprec();         //stoprecording();         if (isrecmode) {             // stop recording             myrec.stop();         }          myrec.release();         super.ondestroy();     }      // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++     // preference variable     // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++      // --------------------------------------------     // method save variable in preference     // --------------------------------------------     public void saveinpreference(string name, string content) {         sharedpreferences preferences = preferencemanager                 .getdefaultsharedpreferences(this);         sharedpreferences.editor editor = preferences.edit();         editor.putstring(name, content);         editor.commit();     }      // --------------------------------------------     // getting content preferences     // --------------------------------------------     public string getfrompreference(string variable_name) {         string preference_return;         sharedpreferences preferences = preferencemanager                 .getdefaultsharedpreferences(this);         preference_return = preferences.getstring(variable_name, "");          return preference_return;     }      // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++     // preference variable     // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++      private void terminateanderasefile() {         try {              toast toast = toast.maketext(this,                     this.getstring(r.string.reciever_end_call),                     toast.length_short);             toast.show();         } catch (illegalstateexception e) {             e.printstacktrace();         }          toast toast = toast.maketext(this,                 this.getstring(r.string.record_impossible), toast.length_long);         toast.show();     }  }