/**
 * Specifies in-memory Set/Map sorting using a specified {@link Comparator} for sorting.
 *
 * NOTE : Sorting is different than ordering (see {@link OrderBy}) which is applied during the SQL SELECT.
 *
 * For sorting based on natural sort order, use {@link SortNatural} instead.  It is illegal to combine
 * {@link SortComparator} and {@link SortNatural}.
 *
 * @see OrderBy
 * @see SortComparator
 *
 * @author Steve Ebersole
 */
@Target({METHOD, FIELD})
@Retention(RUNTIME)
public @interface SortComparator {
    /**
     * Specifies the comparator class to use.
     */
    Class<? extends Comparator<?>> value();
}

在注释中可以看到Set/Map，注解加在List上是不行的，List改成Set就OK了