The application crashes when you click on the notification

There is an activity in which from the first we get a link to the audio stream and play it through ExoPlayer. Also in this activates a notification is built, where information about the current stream and the "Stop" button are displayed. Clicking on the notification opens this activation.

Sometimes (not in all cases) when you click on a notification, the application crashes. In the market, there were about 2000 failures and all come with one mistake practically. As I understand it, the stream variable is empty when I click on the notification. How to fix this moment, maybe I made a mistake in the code? Here is the player code itself

public class Player extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener { private String stream; private String radio; private int img; private boolean isPlay; private String MAYBE_ACTION = "MAYBE_ACTION"; private ImageButton btnPLayPause; private TextView txtRadio; private CircleImageView imgRadio; NotificationManager notificationManager; BandwidthMeter bandwidthMeter; TrackSelector trackSelector; SimpleExoPlayer player; private SimpleExoPlayerView simpleExoPlayerView; BroadcastReceiver br; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_player); Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar); DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); ActionBarDrawerToggle toggle = new ActionBarDrawerToggle( this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close); drawer.setDrawerListener(toggle); toggle.syncState(); NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view); navigationView.setNavigationItemSelectedListener(this); btnPLayPause = (ImageButton) findViewById(R.id.btnPLayPause); txtRadio = (TextView) findViewById(R.id.txtRadio); imgRadio = (CircleImageView) findViewById(R.id.imgRadio); //Получаем текст из списка и ссылку на радио stream = getIntent().getExtras().getString("stream").toString().trim(); radio = getIntent().getExtras().getString("radio").toString().trim(); img = getIntent().getExtras().getInt("img"); imgRadio.setImageResource(img); bandwidthMeter = new DefaultBandwidthMeter(); TrackSelection.Factory streamSelectionFactory = new AdaptiveVideoTrackSelection.Factory(bandwidthMeter); trackSelector = new DefaultTrackSelector(streamSelectionFactory); player = ExoPlayerFactory.newSimpleInstance(this, trackSelector, new DefaultLoadControl()); simpleExoPlayerView = new SimpleExoPlayerView(this); simpleExoPlayerView = (SimpleExoPlayerView) findViewById(R.id.player_view); //Set media controller simpleExoPlayerView.setUseController(true); simpleExoPlayerView.requestFocus(); // Bind the player to the view. simpleExoPlayerView.setPlayer(player); Uri streamUri = Uri.parse(stream); // Measures bandwidth during playback. Can be null if not required. DefaultBandwidthMeter bandwidthMeter = new DefaultBandwidthMeter(); // Produces DataSource instances through which media data is loaded. DataSource.Factory dataSourceFactory = new DefaultDataSourceFactory(this, Util.getUserAgent(this, "yourApplicationName"), bandwidthMeter); // Produces Extractor instances for parsing the media data. ExtractorsFactory extractorsFactory = new DefaultExtractorsFactory(); // This is the MediaSource representing the media to be played. MediaSource mediaSource = new ExtractorMediaSource(streamUri, dataSourceFactory, extractorsFactory, null, null); player.prepare(mediaSource); player.setPlayWhenReady(true); isPlay = true; if (player.getPlayWhenReady() == true) { btnPLayPause.setImageResource(R.drawable.icon_stop); } /*Блок для создания уведомлений*/ notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE); // Намерение для запуска второй активности Intent intent = new Intent(this, Player.class); intent.putExtra("stream", stream); intent.putExtra("radio", radio); PendingIntent pIntent = PendingIntent.getActivity(this, 0, intent, 0); //Намерение для закрытия активности, если нажали кнопку Стоп Intent closeIntent = new Intent(); closeIntent.setAction(MAYBE_ACTION); PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 12345, closeIntent, PendingIntent.FLAG_UPDATE_CURRENT); // Строим уведомление Notification builder = new Notification.Builder(this) .setTicker(radio) .setContentTitle("Играет: " + radio) /*.setContentText("Это я, почтальон Печкин. Принес для вас посылку")*/ .setSmallIcon(R.mipmap.ic_launcher).setContentIntent(pIntent) .addAction(R.drawable.icon_stop, "Стоп", pendingIntent) .build(); //Настойчивое уведомление builder.flags = builder.flags | Notification.FLAG_INSISTENT | Notification.FLAG_ONGOING_EVENT; notificationManager.notify(0, builder); /*Блок для создания уведомлений*/ /*BroadcastReceiver*/ br = new BroadcastReceiver() { @Override // действия при получении сообщений public void onReceive(Context context, Intent intent) { finish(); } }; // создаем фильтр для BroadcastReceiver IntentFilter intentFilter = new IntentFilter(MAYBE_ACTION); // регистрируем (включаем) BroadcastReceiver registerReceiver(br, intentFilter); /*BroadcastReceiver*/ txtRadio.setText(radio); } @Override protected void onDestroy() { NotificationManager notifManager= (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE); notifManager.cancelAll(); super.onDestroy(); player.release(); unregisterReceiver(br); } public void onPlayPause(View view) { if (isPlay == true) { if (player.getPlayWhenReady() == true) { player.setPlayWhenReady(false); isPlay = false; btnPLayPause.setImageResource(R.drawable.icon_play); } } else if (isPlay == false) { if (player.getPlayWhenReady() == false) { player.setPlayWhenReady(true); isPlay = true; btnPLayPause.setImageResource(R.drawable.icon_stop); } } } } 

This is a mistake

 java.lang.RuntimeException: at android.app.ActivityThread.performLaunchActivity (ActivityThread.java:2439) at android.app.ActivityThread.handleLaunchActivity (ActivityThread.java:2499) at android.app.ActivityThread.access$900 (ActivityThread.java:166) at android.app.ActivityThread$H.handleMessage (ActivityThread.java:1360) at android.os.Handler.dispatchMessage (Handler.java:102) at android.os.Looper.loop (Looper.java:148) at android.app.ActivityThread.main (ActivityThread.java:5487) at java.lang.reflect.Method.invoke (Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:765) at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:655) Caused by: java.lang.NullPointerException: at ru.ars.radio.Player.onCreate (Player.java:134) at android.app.Activity.performCreate (Activity.java:6556) at android.app.Instrumentation.callActivityOnCreate (Instrumentation.java:1108) at android.app.ActivityThread.performLaunchActivity (ActivityThread.java:2392) 

Drain 134 is

 stream = getIntent().getExtras().getString("stream").toString().trim(); 

Please tell me how to rewrite this piece of code more correctly? And why such an exception is thrown