Binding installed without paper ui is getting removed with every restart of openhab

I have installed openhab2 in pi , I have added added varoius binding jar in addons folder of openhab2,
But when i restart openhab2 everytime installed bindings gets disappered, and again i have to install it.
The same thing happens with binding installed using paper ui . all bindings get disappeared when openhab is restarted.

Please help me this seem strange