nullPointerException after Screen rotation <p>I get nullPointerException exception returned by object <code>LinearLayout</code> after screen rotation although i am passing null in <code>onCreate()</code> super.onCreate(null); . I know Activity must be destroyed and re-created beside i'm passing savedInstanceState = null that mean Activity should start after rotation as it start for first time, why i get this Exception after rotation ?</p> <p><strong>onCreate() snippet where <code>LinearLayout</code> object called historyText</strong></p> <pre><code>LinearLayout historyText ; // this return exception if it used after rotation . @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(null); setContentView(R.layout.activity_main); historyText = (LinearLayout) findViewById(R.id.historyLayoutText); Log.e("HISTORYVISIBILITY", "VISIBILITY = "+historyText.getVisibility()); getWindow().getDecorView().setSystemUiVisibility( View.SYSTEM_UI_FLAG_LAYOUT_STABLE | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN); database = new Database(this); Bundle extras = getIntent().getExtras(); intent = extras.getInt("activity"); p = new Progress(); getSupportFragmentManager().beginTransaction() .add(R.id.group, p) .commit(); orientation = getRotation(); switch (orientation){ case "p" : addPlus(); } } </code></pre> <p><strong>Logcat</strong></p> <pre><code> 10-07 22:21:24.365: E/AndroidRuntime(7768): FATAL EXCEPTION: main 10-07 22:21:24.365: E/AndroidRuntime(7768): Process: developer.mohab.gymee, PID: 7768 10-07 22:21:24.365: E/AndroidRuntime(7768): java.lang.RuntimeException: Unable to start activity ComponentInfo{developer.mohab.gymee/developer.mohab.gymee.Cardio.Cardio}: java.lang.NullPointerException: Attempt to invoke virtual method 'int android.widget.LinearLayout.getVisibility()' on a null object reference 10-07 22:21:24.365: E/AndroidRuntime(7768): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2379) 10-07 22:21:24.365: E/AndroidRuntime(7768): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2442) 10-07 22:21:24.365: E/AndroidRuntime(7768): at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4053) 10-07 22:21:24.365: E/AndroidRuntime(7768): at android.app.ActivityThread.access$900(ActivityThread.java:156) 10-07 22:21:24.365: E/AndroidRuntime(7768): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1357) 10-07 22:21:24.365: E/AndroidRuntime(7768): at android.os.Handler.dispatchMessage(Handler.java:102) 10-07 22:21:24.365: E/AndroidRuntime(7768): at android.os.Looper.loop(Looper.java:211) 10-07 22:21:24.365: E/AndroidRuntime(7768): at android.app.ActivityThread.main(ActivityThread.java:5389) 10-07 22:21:24.365: E/AndroidRuntime(7768): at java.lang.reflect.Method.invoke(Native Method) 10-07 22:21:24.365: E/AndroidRuntime(7768): at java.lang.reflect.Method.invoke(Method.java:372) 10-07 22:21:24.365: E/AndroidRuntime(7768): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1020) 10-07 22:21:24.365: E/AndroidRuntime(7768): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:815) 10-07 22:21:24.365: E/AndroidRuntime(7768): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'int android.widget.LinearLayout.getVisibility()' on a null object reference 10-07 22:21:24.365: E/AndroidRuntime(7768): at developer.mohab.gymee.Cardio.Cardio.onCreate(Cardio.java:76) 10-07 22:21:24.365: E/AndroidRuntime(7768): at android.app.Activity.performCreate(Activity.java:5990) 10-07 22:21:24.365: E/AndroidRuntime(7768): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106) 10-07 22:21:24.365: E/AndroidRuntime(7768): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2332) 10-07 22:21:24.365: E/AndroidRuntime(7768): ... 11 more 10-07 22:21:24.633: E/SurfaceFlinger(319): rejecting buffer: bufWidth=1358, bufHeight=624, front.active.{w=193, h=193} </code></pre>