It'd be great to specify result transformation logic in Lambda-style when running on Java 8:

session.createQuery( "SELECT foo, bar FROM Baz" )
    .transformResultTuples( (tuple, aliases) -> { return tuple[0] + " " + tuple[1]; } )
    .list();

That requires an interface with a single abstract method ("functional interface") describing the Lambda type. The current ResultTransformer interface has two methods, so it cannot be used as is.

Proposal: Deprecate ResultTransformer and add two new, separate contracts as replacement: ResultRowTransformer and ResultListTransformer. Query#setResultTransformer() would be superseded by two new methods: transformResultTuples() and transformResultList().

Note that this change is fully compatible with previous Java versions: One still can pass an (anonymous) implementation of one or both of the contracts when stuck to Java 6/7:

session.createQuery( "SELECT foo, bar FROM Baz" )
    .transformResultTuples( new ResultRowTransformer() {
        public Object transformTuple(Object[] tuple, String[] aliases) {
            return return tuple[0] + " " + tuple[1]; 
        }
    } )
    .list();

It's just a tad more verbose.