AppCrashOnSecondRecipe.log

E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.example.android.bakingapp, PID: 4605
                  java.lang.NullPointerException: Attempt to read from field 'int android.support.v4.app.Fragment.mIndex' on a null object reference
                      at android.support.v4.app.FragmentManagerImpl.putFragment(FragmentManager.java:860)
                      at com.example.android.bakingapp.RecipeActivity.onSaveInstanceState(RecipeActivity.java:160)
                      at android.app.Activity.performSaveInstanceState(Activity.java:1414)
                      at android.app.Instrumentation.callActivityOnSaveInstanceState(Instrumentation.java:1300)
                      at android.app.ActivityThread.callCallActivityOnSaveInstanceState(ActivityThread.java:4541)
                      at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3856)
                      at android.app.ActivityThread.handleStopActivity(ActivityThread.java:3915)
                      at android.app.ActivityThread.-wrap25(ActivityThread.java)
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1511)
                      at android.os.Handler.dispatchMessage(Handler.java:102)
                      at android.os.Looper.loop(Looper.java:154)
                      at android.app.ActivityThread.main(ActivityThread.java:6119)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)