Set<String> enemies = Sets.newHashSet("Dick", "Harry", "Tom");

    Set<String> goodFriends = Sets.difference(friends, enemies);
    assertEquals(2, goodFriends.size());

    ImmutableSet<String> immut = Sets.difference(friends, enemies).immutableCopy();
    HashSet<String> mut = Sets.difference(friends, enemies).copyInto(new HashSet<String>());

    enemies.add("Dave");
    assertEquals(1, goodFriends.size());

						</difference>
						<difference>
							<className>jcifs/Configuration</className>
							<differenceType>7012</differenceType>
							<method>java.lang.String getGuestPassword()</method>
						</difference>
						<difference>
							<className>jcifs/SmbResource</className>
							<differenceType>7012</differenceType>
							<method>void setFileTimes(long, long, long)</method>
						</difference>
					</ignored>

    Set<String> enemies = Sets.newHashSet("Dick", "Harry", "Tom");

    Set<String> goodFriends = Sets.difference(friends, enemies);
    assertEquals(2, goodFriends.size());

    ImmutableSet<String> immut = Sets.difference(friends, enemies).immutableCopy();
    HashSet<String> mut = Sets.difference(friends, enemies).copyInto(new HashSet<String>());

    enemies.add("Dave");
    assertEquals(1, goodFriends.size());

    MapDifference<Integer, String> original = Maps.difference(left, right);
    MapDifference<Integer, String> same = Maps.difference(left, right);
    MapDifference<Integer, String> reverse = Maps.difference(right, left);
    MapDifference<Integer, String> diff2 = Maps.difference(left, right2);

    new EqualsTester()
        .addEqualityGroup(original, same)

    MapDifference<Integer, String> original = Maps.difference(left, right);
    MapDifference<Integer, String> same = Maps.difference(left, right);
    MapDifference<Integer, String> reverse = Maps.difference(right, left);
    MapDifference<Integer, String> diff2 = Maps.difference(left, right2);

    new EqualsTester()
        .addEqualityGroup(original, same)

		nrules[pattern] = nrules[pattern].Union(targetIDSet)
	}

	return nrules
}

// Difference - returns difference with given rules as new rules.
func (rules Rules) Difference(rules2 Rules) Rules {
	nrules := make(Rules)

	for pattern, targetIDSet := range rules {
		if nv := targetIDSet.Difference(rules2[pattern]); len(nv) > 0 {
			nrules[pattern] = nv
		}
	}

	return nrules

func (set TargetIDSet) Union(sset TargetIDSet) TargetIDSet {
	nset := set.Clone()

	for k := range sset {
		nset.add(k)
	}

	return nset
}

// Difference - returns difference with given set as new set.
func (set TargetIDSet) Difference(sset TargetIDSet) TargetIDSet {
	nset := NewTargetIDSet()
	for k := range set {
		if _, ok := sset[k]; !ok {
			nset.add(k)
		}
	}

	return nset
}

    assertThat(Multisets.difference(ms1, ms2)).containsExactly("a", "b");
  }

  public void testDifferenceWithRemovedElement() {
    Multiset<String> ms1 = HashMultiset.create(Arrays.asList("a", "b", "a"));
    Multiset<String> ms2 = HashMultiset.create(Arrays.asList("b"));
    assertThat(Multisets.difference(ms1, ms2)).containsExactly("a", "a");
  }

func (set TargetIDSet) Union(sset TargetIDSet) TargetIDSet {
	nset := set.Clone()

	for k := range sset {
		nset.add(k)
	}

	return nset
}

// Difference - returns difference with given set as new set.
func (set TargetIDSet) Difference(sset TargetIDSet) TargetIDSet {
	nset := NewTargetIDSet()
	for k := range set {
		if _, ok := sset[k]; !ok {
			nset.add(k)
		}
	}

	return nset
}

    assertThat(Multisets.difference(ms1, ms2)).containsExactly("a", "b");
  }

  public void testDifferenceWithRemovedElement() {
    Multiset<String> ms1 = HashMultiset.create(Arrays.asList("a", "b", "a"));
    Multiset<String> ms2 = HashMultiset.create(Arrays.asList("b"));
    assertThat(Multisets.difference(ms1, ms2)).containsExactly("a", "a");
  }