assertThrows(IllegalArgumentException.class, () -> range.gap(Range.closed(4, 6)));
    assertThrows(IllegalArgumentException.class, () -> range.gap(Range.closed(2, 4)));
    assertThrows(IllegalArgumentException.class, () -> range.gap(Range.closed(2, 3)));
  }

  public void testGap_invalidRangesWithInfinity() {
    assertThrows(IllegalArgumentException.class, () -> Range.atLeast(1).gap(Range.atLeast(2)));

    assertThrows(IllegalArgumentException.class, () -> range.gap(Range.closed(4, 6)));
    assertThrows(IllegalArgumentException.class, () -> range.gap(Range.closed(2, 4)));
    assertThrows(IllegalArgumentException.class, () -> range.gap(Range.closed(2, 3)));
  }

  public void testGap_invalidRangesWithInfinity() {
    assertThrows(IllegalArgumentException.class, () -> Range.atLeast(1).gap(Range.atLeast(2)));

   *
   * <p>For example, the gap of {@code [1..5]} and {@code (7..10)} is {@code (5..7]}. The resulting
   * range may be empty; for example, the gap between {@code [1..5)} {@code [5..7)} yields the empty
   * range {@code [5..5)}.
   *
   * <p>The gap exists if and only if the two ranges are either disconnected or immediately adjacent

   */
  private static String hextetsToIPv6String(int[] hextets) {
    // While scanning the array, handle these state transitions:
    //   start->num => "num"     start->gap => "::"
    //   num->num   => ":num"    num->gap   => "::"
    //   gap->num   => "num"     gap->gap   => ""
    StringBuilder buf = new StringBuilder(39);
    boolean lastWasNumber = false;
    for (int i = 0; i < hextets.length; i++) {

   */
  private static String hextetsToIPv6String(int[] hextets) {
    // While scanning the array, handle these state transitions:
    //   start->num => "num"     start->gap => "::"
    //   num->num   => ":num"    num->gap   => "::"
    //   gap->num   => "num"     gap->gap   => ""
    StringBuilder buf = new StringBuilder(39);
    boolean lastWasNumber = false;
    for (int i = 0; i < hextets.length; i++) {

 *
 * <p>In light of the significant enhancements to {@code Comparator} in Java 8, the overwhelming
 * majority of usages of {@code Ordering} can be written using only built-in JDK APIs. This class is
 * intended to "fill the gap" and provide those features of {@code Ordering} not already provided by
 * the JDK.
 *
 * @since 21.0
 * @author Louis Wasserman
 */
@GwtCompatible
public final class Comparators {
  private Comparators() {}