JazzyViewpager Not working Properly about jazzyviewpager HOT 2 OPEN

Have you implemented the instantiateItem(ViewGroup container, final int position) method in the adapter

from jazzyviewpager.

Yes i did but its java.lang.NullPointerException exception if i do .
Here's the code :
public JazzyViewPager viewPager;
public Object instantiateItem(ViewGroup container, final int position) {
Object obj = super.instantiateItem(container, position);
viewPager.setObjectForPosition(obj, position);
return obj;
}

from jazzyviewpager.