.getOrDefault(artifact.getGroupId(), Collections.emptyMap())
                .getOrDefault(artifact.getArtifactId(), Collections.emptyMap())
                .values()
                .stream()
                .filter(p -> Objects.nonNull(findArtifact(p, artifact)))
                .map(MavenProject::getVersion)
                .collect(Collectors.collectingAndThen(Collectors.toList(), Collections::unmodifiableList));
    }

            Map<?, ?> map = (Map) session.getCache().get(session, DefaultModelCache.class.getName());
            List<String> paths = map.keySet().stream()
                    .map(Object::toString)
                    .filter(s -> s.startsWith("SourceCacheKey"))
                    .map(s -> s.substring("SourceCacheKey[location=".length(), s.indexOf(", tag")))
                    .sorted()
                    .distinct()

    }

    private static final long serialVersionUID = 5;
  }

  public void testMutableValues() {
    IntHolder holderA = new IntHolder(1);
    IntHolder holderB = new IntHolder(2);
    Map<String, IntHolder> map = ImmutableMap.of("a", holderA, "b", holderB);
    holderA.value = 3;
    assertTrue(map.entrySet().contains(Maps.immutableEntry("a", new IntHolder(3))));