when i create fragment then it overlap on action bar

When you facing problem your action bar is getting overlapped by other activity.

Because you using frame layout add the following line in frame layout.

android:layout_marginTop="?attr/actionBarSize"

Like this it will resolve the problem of action bar overlapped actionbar.
in app_bar_main.xml

<FrameLayout    android:layout_width="match_parent"    android:layout_marginTop="?attr/actionBarSize"

android:layout_height="match_parent">