Move the cursor forward one row from its current row position.
Caution: next() method and iterator() method share same data structure.
Please don't use them together.
Caution: In case ResultSet is obtained from QueryChangeListener, and QueryChangeListener is
already removed from Query, ResultSet is already freed. And this next() method returns null.
the Result after moving the cursor forward. Returns null value
if there are no more rows, or ResultSet is freed already.
Return List of Results. List is unmodifiable and only supports
int get(int index), int size(), boolean isEmpty() and Iterator iterator() methods.
Once called allResults(), next() method return null. Don't call next() and allResults()