NullPointerException

[alcntml]

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tmob.deneme/com.xxxx.src.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.ActionBar.setBackgroundDrawable(android.graphics.drawable.Drawable)' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2305) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2367) at android.app.ActivityThread.access$800(ActivityThread.java:148) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1283) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5274) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:909) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:704) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.ActionBar.setBackgroundDrawable(android.graphics.drawable.Drawable)' on a null object reference at com.achep.header2actionbar.FadingActionBarHelper.setActionBarBackgroundDrawable(FadingActionBarHelper.java:52) at com.achep.header2actionbar.FadingActionBarHelper.setActionBarBackgroundDrawable(FadingActionBarHelper.java:47) at com.achep.header2actionbar.FadingActionBarHelper.(FadingActionBarHelper.java:43) at com.xxxx.src.MainActivity.onCreate(MainActivity.java:37) at android.app.Activity.performCreate(Activity.java:5977) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2258)             at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2367)             at android.app.ActivityThread.access$800(ActivityThread.java:148)             at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1283)             at android.os.Handler.dispatchMessage(Handler.java:102)             at android.os.Looper.loop(Looper.java:135)             at android.app.ActivityThread.main(ActivityThread.java:5274)             at java.lang.reflect.Method.invoke(Native Method)             at java.lang.reflect.Method.invoke(Method.java:372)             at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:909)             at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:704)