Several potential NullPointerException bugs

Hi all,
Our bug scanner has reported some NPE bugs.

The bugs are caused by the

return null

in function retrieve()

Since the return value of the method retrieve() may be null , a NPE bug may take place in retrieve() when the return value of the method retrieve() was passed to the first parameter of the method retrieve() .
And when the return value of the method retrieve() was passed to the parameter of the method filterParams() , a NPE bug may also occur.

Thanks.