Collector<Entry<String, Integer>, ?, ImmutableSortedMap<String, Integer>> collector =
        ImmutableSortedMap.toImmutableSortedMap(
            String.CASE_INSENSITIVE_ORDER, Entry::getKey, Entry::getValue);
    BiPredicate<ImmutableSortedMap<String, Integer>, ImmutableSortedMap<String, Integer>>
        equivalence =
            Equivalence.equals()
                .onResultOf(ImmutableSortedMap<String, Integer>::comparator)

  public void testToImmutableSortedMap_java7_combine() {
    ImmutableSortedMap.Builder<String, Integer> zis =
        ImmutableSortedMap.<String, Integer>naturalOrder().put("one", 1).put("four", 4);
    ImmutableSortedMap.Builder<String, Integer> zat =
        ImmutableSortedMap.<String, Integer>naturalOrder().put("two", 2).put("three", 3);
    ImmutableSortedMap<String, Integer> sortedMap = zis.combine(zat).build();