This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
public static interface QueryWrapper.QueryRunnable
A QueryRunnable implementation is passed to the QueryWrapper on execute of
the query to process the resulting ResultSet. This allows the enforcement
of the correct threading behaviour for any hits to the database (i.e. the
ResultSet iteration) as the wrapper framework can ensure that the ResultSet
is processed, and then closed.