title: Android Studio: Unfortunately app has stopped
body: <p>When i try to run my app, "Unfortunately, “app” has Stopped" pop on the screen. I have researched this problem and tried of changing code in manifest file. Also I tried many times cleaning project, rebuilding project, Invalidate Cache and restart option but this also doesn't help in solving problem.</p>
  
  <p>Here is the error shown in my logcat </p>
  
  <pre><code>02-21 09:26:52.695 3123-3123/? E/memtrack: Couldn't load memtrack module (No such file or directory)
  02-21 09:26:52.695 3123-3123/? E/android.os.Debug: failed to load memtrack module: -2
  02-21 09:26:56.587 3137-3137/? E/memtrack: Couldn't load memtrack module (No such file or directory)
  02-21 09:26:56.587 3137-3137/? E/android.os.Debug: failed to load memtrack module: -2
  02-21 09:26:57.611 3147-3147/com.example.nobelz.chatapp E/dalvikvm: Could not find class 'android.graphics.drawable.RippleDrawable', referenced from method android.support.v7.widget.AppCompatImageHelper.hasOverlappingRendering
  02-21 09:26:58.231 3147-3147/com.example.nobelz.chatapp E/OpenGLRenderer: Getting MAX_TEXTURE_SIZE from GradienCache
  02-21 09:26:58.235 3147-3147/com.example.nobelz.chatapp E/OpenGLRenderer: MAX_TEXTURE_SIZE: 8192
  02-21 09:26:58.259 3147-3147/com.example.nobelz.chatapp E/OpenGLRenderer: Getting MAX_TEXTURE_SIZE from Caches::initConstraints()
  02-21 09:26:58.263 3147-3147/com.example.nobelz.chatapp E/OpenGLRenderer: MAX_TEXTURE_SIZE: 8192
  02-21 09:27:02.323 3147-3147/com.example.nobelz.chatapp E/AndroidRuntime: FATAL EXCEPTION: main 
  Process: com.example.nobelz.chatapp, PID: 3147   
  com.google.firebase.database.DatabaseException: Class     com.example.nobelz.chatapp.ChatMessage is missing a constructor with no arguments
                                                                            at com.google.android.gms.internal.zzbqi$zza.zze(Unknown Source)
                                                                            at com.google.android.gms.internal.zzbqi$zza.zzaG(Unknown Source)
                                                                            at com.google.android.gms.internal.zzbqi.zze(Unknown Source)
                                                                            at com.google.android.gms.internal.zzbqi.zzb(Unknown Source)
                                                                            at com.google.android.gms.internal.zzbqi.zza(Unknown Source)
                                                                            at com.google.firebase.database.DataSnapshot.getValue(Unknown Source)
                                                                            at com.firebase.ui.database.FirebaseListAdapter.parseSnapshot(FirebaseListAdapter.java:127)
                                                                            at com.firebase.ui.database.FirebaseListAdapter.getItem(FirebaseListAdapter.java:116)
                                                                            at com.firebase.ui.database.FirebaseListAdapter.getView(FirebaseListAdapter.java:146)
                                                                            at android.widget.AbsListView.obtainView(AbsListView.java:2255)
                                                                            at android.widget.ListView.makeAndAddView(ListView.java:1790)
                                                                            at android.widget.ListView.fillDown(ListView.java:691)
                                                                            at android.widget.ListView.fillFromTop(ListView.java:752)
                                                                            at android.widget.ListView.layoutChildren(ListView.java:1616)
                                                                            at android.widget.AbsListView.onLayout(AbsListView.java:2087)
                                                                            at android.view.View.layout(View.java:14817)
                                                                            at android.view.ViewGroup.layout(ViewGroup.java:4631)
                                                                            at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1055)
                                                                            at android.view.View.layout(View.java:14817)
                                                                            at android.view.ViewGroup.layout(ViewGroup.java:4631)
                                                                            at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
                                                                            at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
                                                                            at android.view.View.layout(View.java:14817)
                                                                            at android.view.ViewGroup.layout(ViewGroup.java:4631)
                                                                            at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:437)
                                                                            at android.view.View.layout(View.java:14817)
                                                                            at android.view.ViewGroup.layout(ViewGroup.java:4631)
                                                                            at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
                                                                            at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
                                                                            at android.view.View.layout(View.java:14817)
                                                                            at android.view.ViewGroup.layout(ViewGroup.java:4631)
                                                                            at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
                                                                            at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
                                                                            at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
                                                                            at android.view.View.layout(View.java:14817)
                                                                            at android.view.ViewGroup.layout(ViewGroup.java:4631)
                                                                            at android.widget.FrameLayout.layoutChildren(FrameLayout.java:453)
                                                                            at android.widget.FrameLayout.onLayout(FrameLayout.java:388)
                                                                            at android.view.View.layout(View.java:14817)
                                                                            at android.view.ViewGroup.layout(ViewGroup.java:4631)
                                                                            at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1983)
                                                                            at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1740)
                                                                            at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:996)
                                                                            at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5600)
                                                                            at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
                                                                            at android.view.Choreographer.doCallbacks(Choreographer.java:574)
                                                                            at android.view.Choreographer.doFrame(Choreographer.java:544)
                                                                            at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
                                                                            at android.os.Handler.handleCallback(Handler.java:733)
                                                                            at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                            at android.os.Looper.loop(Looper.java:136)
                                                                            at android.app.ActivityThread.main(ActivityThread.java:5001)
                                                                            at java.lang.reflect.Method.invokeNative(Native Method)
                                                                            at java.lang.reflect.Method.invoke(Method.java:515)
                                                                            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
                                                                            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
                                                                            at dalvik.system.NativeStart.main(Native Method)
  02-21 09:27:07.367 560-593/system_process E/InputDispatcher: channel '52c1f3d8 com.example.nobelz.chatapp/com.example.nobelz.chatapp.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
  02-21 09:31:38.407 232-232/? E/Drm: Failed to open plugin directory /vendor/lib/mediadrm
  02-21 09:32:05.543 859-1264/com.google.process.gapps E/dalvikvm: Could not find class 'android.net.Network', referenced from method qlb.a
  02-21 09:34:38.537 859-1421/com.google.process.gapps E/NetworkScheduler: Called closeAndCleanupTask for already completed task  [com.google.android.apps.maps/com.google.android.apps.gmm.offline.OfflineAutoUpdateGcmService:OfflineAutoUpdateGcmService.TASK_TAG,u0]' :TIMED_OUT
  02-21 09:34:38.573 859-1421/com.google.process.gapps E/NetworkScheduler: Task completed but with no record in list of active tasks: [com.google.android.apps.maps/com.google.android.apps.gmm.offline.OfflineAutoUpdateGcmService:OfflineAutoUpdateGcmService.TASK_TAG,u0]
  02-21 09:34:40.793 3391-3391/? E/dalvikvm: Could not find class 'javax.net.ssl.SNIHostName', referenced from method com.google.android.gms.org.conscrypt.Platform.getSSLParameters
  02-21 09:34:40.797 3391-3391/? E/dalvikvm: Could not find class 'javax.net.ssl.SNIServerName', referenced from method com.google.android.gms.org.conscrypt.Platform.setSSLParameters
  02-21 09:34:40.805 3391-3391/? E/dalvikvm: Could not find class 'com.google.android.gms.org.conscrypt.OpenSSLExtendedSessionImpl', referenced from method com.google.android.gms.org.conscrypt.Platform.wrapSSLSession
  02-21 09:34:40.833 725-725/com.google.android.gms.persistent E/ChimeraRcvrProxy: Chimera config error: com.google.android.chimera.config.InvalidConfigException: No registered Chimera receiver impl for ComponentInfo{com.google.android.gms/com.google.android.gms.phenotype.receiver.PhenotypeBroadcastReceiver}
  02-21 09:34:40.833 725-725/com.google.android.gms.persistent E/ChimeraRcvrProxy: com.google.android.gms.phenotype.receiver.PhenotypeBroadcastReceiver dropping broadcast com.google.android.gms.phenotype.UPDATE
  02-21 09:34:40.913 3391-3391/? E/dalvikvm: Could not find class 'com.google.android.gms.org.conscrypt.OpenSSLExtendedSessionImpl', referenced from method com.google.android.gms.org.conscrypt.SSLParametersImpl.getSessionToReuse
  02-21 09:34:41.169 725-725/com.google.android.gms.persistent E/BluetoothAdapter: Bluetooth binder is null
  02-21 09:34:41.645 725-725/com.google.android.gms.persistent E/BluetoothAdapter: Bluetooth binder is null
  02-21 09:34:41.709 725-3425/com.google.android.gms.persistent E/GCoreUlr: Bad errorId configuring silent feedback
  02-21 09:34:41.937 725-725/com.google.android.gms.persistent   E/BluetoothAdapter: Bluetooth binder is null
  02-21 09:34:42.013 725-1235/com.google.android.gms.persistent E/GCoreUlr: Bad errorId configuring silent feedback
  02-21 09:34:42.069 725-725/com.google.android.gms.persistent E/BluetoothAdapter: Bluetooth binder is null
  02-21 09:34:42.161 725-1235/com.google.android.gms.persistent E/GCoreUlr: Bad errorId configuring silent feedback
  02-21 09:34:42.265 725-1235/com.google.android.gms.persistent E/GCoreUlr: Bad errorId configuring silent feedback
  02-21 09:34:42.309 725-1235/com.google.android.gms.persistent E/GCoreUlr: Bad errorId configuring silent feedback
  02-21 09:35:10.173 560-567/system_process E/dalvikvm: JIT code cache full
  </code></pre>