java - threadid=1: thread exiting with uncaught exception error -

i'm recieving error of threadid=1... don't @ point in app @ sometime. not sure specific error is. i've check line 164 , don't see cause result. maybe need add manifest? here logcat.

05-08 17:19:28.796: w/dalvikvm(8683): threadid=1: thread exiting uncaught exception (group=0x40e37438) 05-08 17:19:28.806: e/androidruntime(8683): fatal exception: main 05-08 17:19:28.806: e/androidruntime(8683): java.lang.nullpointerexception 05-08 17:19:28.806: e/androidruntime(8683):     @ com.example.speech.mainactivity$speechlistener.onresults(mainactivity.java:164) 05-08 17:19:28.806: e/androidruntime(8683):     @ android.speech.speechrecognizer$internallistener$1.handlemessage(speechrecognizer.java:442) 05-08 17:19:28.806: e/androidruntime(8683):     @ android.os.handler.dispatchmessage(handler.java:99) 05-08 17:19:28.806: e/androidruntime(8683):     @ android.os.looper.loop(looper.java:137) 05-08 17:19:28.806: e/androidruntime(8683):     @ android.app.activitythread.main(activitythread.java:4918) 05-08 17:19:28.806: e/androidruntime(8683):     @ java.lang.reflect.method.invokenative(native method) 05-08 17:19:28.806: e/androidruntime(8683):     @ java.lang.reflect.method.invoke(method.java:511) 05-08 17:19:28.806: e/androidruntime(8683):     @ com.android.internal.os.zygoteinit$methodandargscaller.run(zygoteinit.java:1004) 05-08 17:19:28.806: e/androidruntime(8683):     @ com.android.internal.os.zygoteinit.main(zygoteinit.java:771) 05-08 17:19:28.806: e/androidruntime(8683):     @ dalvik.system.nativestart.main(native method) 

here main activity code: package com.example.speech;

import java.util.arraylist;  import android.media.audiomanager; import android.media.mediaplayer; import android.os.build; import android.os.bundle; import android.os.countdowntimer; import android.app.activity; import android.content.intent; import android.speech.recognitionlistener; import android.speech.recognizerintent; import android.speech.speechrecognizer; import android.view.menu; import android.view.view.onclicklistener; import android.view.view; import android.widget.arrayadapter; import android.widget.button; import android.widget.listview; import android.util.log;  public class mainactivity extends activity implements  onclicklistener {  private speechrecognizer mspeechrecognizer; private intent mspeechrecognizerintent;  boolean reseter = false; private audiomanager maudiomanager; private volatile boolean mnospeechcountdownon; mediaplayer testsound;   @override protected void oncreate(bundle savedinstancestate) {       super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);     boolean available = speechrecognizer.isrecognitionavailable(this);     log.d("speech", "available = " + available);     testsound = mediaplayer.create(mainactivity.this, r.raw.soundclip);     mspeechrecognizer = speechrecognizer.createspeechrecognizer(this);     mspeechrecognizer.setrecognitionlistener(new speechlistener());     mspeechrecognizerintent = new intent(recognizerintent.action_recognize_speech);     mspeechrecognizerintent.putextra(recognizerintent.extra_language_model,             recognizerintent.language_model_free_form);     mspeechrecognizerintent.putextra(recognizerintent.extra_calling_package,             this.getpackagename());     mspeechrecognizerintent.putextra(recognizerintent.extra_speech_input_complete_silence_length_millis, 0);     maudiomanager = (audiomanager) getsystemservice(this.audio_service);     mspeechrecognizer.startlistening(mspeechrecognizerintent);     maudiomanager.setstreammute(audiomanager.stream_system, true);     log.d("speech", "mute on");     try {         thread.sleep(4000);         log.d("speech", "repeat");         mspeechrecognizer.startlistening(mspeechrecognizerintent);         maudiomanager.setstreammute(audiomanager.stream_system, true);         log.d("speech", "mute on");     } catch (interruptedexception e) {     }   }  private countdowntimer mnospeechcountdown = new countdowntimer(5000, 5000) {        @override     public void ontick(long millisuntilfinished)     {      }      @suppresswarnings("synthetic-access")     @override     public void onfinish()     {         mnospeechcountdownon = false;         mspeechrecognizer.cancel();         mspeechrecognizer.startlistening(mspeechrecognizerintent);     } };  @override public boolean oncreateoptionsmenu(menu menu) {     // inflate menu; adds items action bar if present.     getmenuinflater().inflate(r.menu.main, menu);     return true; }   private class speechlistener implements recognitionlistener {       @override     public void onbeginningofspeech() {          if (mnospeechcountdownon)         {             mnospeechcountdownon = false;             mnospeechcountdown.cancel();         }         log.d("speech", "onbeginningofspeech");      }      @override     public void onbufferreceived(byte[] buffer) {         log.d("speech", "onbufferreceived");     }      @override     public void onendofspeech() {         log.d("speech", "onendofspeech");       }      @override     public void onerror(int error) {          if (mnospeechcountdownon)         {             mnospeechcountdownon = false;             mnospeechcountdown.cancel();         }         log.d("speech", "onerror");     }      @override     public void onevent(int eventtype, bundle params) {         log.d("speech", "onevent");     }      @override     public void onpartialresults(bundle partialresults) {         log.d("speech", "onpartialresults");     }      @override     public void onreadyforspeech(bundle params) {         if (build.version.sdk_int >= build.version_codes.jelly_bean)         {             mnospeechcountdownon = true;             mnospeechcountdown.start();             maudiomanager.setstreammute(audiomanager.stream_system, false);         }         log.d("speech", "onreadyforspeech");         try {             thread.sleep(6000);             log.d("speech", "repeat");             mspeechrecognizer.startlistening(mspeechrecognizerintent);             maudiomanager.setstreammute(audiomanager.stream_system, true);             log.d("speech", "mute on");         } catch (interruptedexception e) {         }}     @override     public void onresults(bundle results) {         log.d("speech", "results");            arraylist<string> matches = results.getstringarraylist(speechrecognizer.results_recognition);         (string match : matches) { if (match.equals("one"))  testsound.start();                 else if (match.equals("two")) testsound.start();         }         // whatever want here         try {             thread.sleep(1);             log.d("speech", "repeat");             mspeechrecognizer.startlistening(mspeechrecognizerintent);             maudiomanager.setstreammute(audiomanager.stream_system, true);             log.d("speech", "mute on");         } catch (interruptedexception e) {         }     }     @override     public void onrmschanged(float rmsdb) {         //log.d("speech", "onrmschanged");     }  }   @override public void onclick(view arg0) {     //must keep onclick  } } 

arraylist<string> matches = results.getstringarraylist(speechrecognizer.results_recognition); if(matches!=null) {     (string match : matches)     /* ... */ } 

matches may null if there no matches.