This document provides an agenda and summary for a presentation comparing several popular Java collection frameworks, including the Java Collections Framework, Apache Commons Collections, Eclipse Collections, Google Guava, and Vavr. The presentation will explore the features and capabilities of each framework, perform benchmarks to compare performance on common use cases like creating and manipulating a deck of cards, and analyze the memory usage of data structures in each library. The goal is to help attendees choose the most appropriate collection library for their needs.

1. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Collections.compare(() -> {
JDK; Apache; Eclipse; Guava...});
Donald Raab
Leonardo Lima
Nikhil J. Nanivadekar

2. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Abstract
— Collections are a staple in any programming language: the need to collect, sort or iterate over values is needed by nearly all
developers.
The Java language introduced the Collections framework long ago and that's what many (incredibly not all!) developers learn
when they start programming. It has plenty to offer, but many find it lacking: the amount of collection libraries as active open
source projects demonstrate the need for something else.
If we were to search to find a holistic comparison of famous collection libraries, there is not much literature available. The talk
is poised to fill this gap. In this session, we will explore the most common collections (pun intended!) frameworks, what they
have to offer and what you should consider for your next project.
We will also show common programmer use cases, how each library handles them and the impact on memory, processing
power and ease of use/coding.
After this session, you will be able to choose the right bag for your tricks!

3. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Agenda
1. Brief introduction of who we are (2 min)
2. A bit of history about the Java Util Collections framework (6 min), with a timeline of Java releases and what was
introduced in its collection
3. Show the gaps in use cases from that timeline (6 min)
4. Introduce a timeline with other collection frameworks (6 min, 2 min per framework: Apache, Eclipse, Google)
5. Comparison table with use case / packages diagram (5+ min)
6. Examples of said use cases in IDE (10 min)
7. Actual tests with speed and memory use per solution (rest of time)

4. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
About the Speakers
—Donald Raab
• Managing Director at BNY Mellon
• Based in Jersey City, New Jersey
• Creator of Eclipse Collections
• Member of JSR 335 Expert Group (Lambdas/Streams 4 Java)
• Presenter at Devoxx US, JavaOne, EclipseCon, JVMLS, GIDS

5. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
About the Speakers
—Leonardo Lima
• Computer engineer, server & embedded sw developer
• From São Paulo, Brasil, currently in Austin, TX
• CTO at V2COM
• Spec Lead – JSR363 – Units of Measurement
• V2COM’s Representative at JCP Executive Committee
[about.me/leomrlima]

6. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
—Nikhil J. Nanivadekar
• Mechanical Engineer
• Software developer
• Vice President Technology at Goldman Sachs
• From Pune, India, currently in Salt Lake City, Utah
About the Speakers

7. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
java.util.Collections

8. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
java.util Collections
— Java Collection Framework has been around since 1998/JDK 1.2.
Very basic but critical collection support for Java.
— Interfaces: Maps and Collections (List, Set, Queue, Deque)
— Implementations: Basic and Concurrent versions of the
interfaces, sorted and concurrent as well
— Algorithms: Sorting, Shuffling, Routine Data Manipulation,
Searching, Composition
— Best way to get started is using the simple and concurrent tutorials

9. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Java 2
1998
• Interfaces
• Collection
• List
• Set
• Map
• List
• SortedMap
Java 5
2005
• Generics
• For-each loop
• Interfaces
• Iterable
• Queue
• ConcurrentMap
• BlockingQueue
Java 6
2006
•Interfaces
•NavigableSet
•NavigableMap
•Deque
•BlockingDeque
•ConcurrentNavigableMap
Java 7
2011
• Interfaces
• TransferQueu
e
Java 8
2014
• Lambdas
• Method Refs
• Default Methods
• Interfaces
• BaseStream
• Stream
• IntStream
• LongStream
• DoubleStream
• Collector
• Spliterator
• PrimitiveIterator
Java 9
2017
• JPMS
• Collection
Factory
methods
• New Stream
APIs
• Improved
Javadoc
• Private
interface
methods
Java Collections Framework

10. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
!java.util.Collections?

11. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
!java.util Collections
— We’re comparing 4 other collection frameworks,
and JDK 8 Collections. In alphabetical order:
— Apache Commons Collections (v 4.1)
— Eclipse Collections (fka GS Collections, v 9.0)
— Google Guava’s Collections (v23)
— Vavr’s Collections (fka Javaslang, v0.9)
— (links are to their user guide/documentation!)

12. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Collection Frameworks Timeline
Java 2
1998
• Jakarta
Collections 1.0
• 2001
• Apache
Collections 3.0
(AC)
• 2004
Java 6
2006
• Google
Collections 1.0
• Dec. 2009
Java 7
2011
• Google Guava
10.0
• Sept. 2011
• GS Collections
1.0
• Jan. 2012
• AC 4.0
• Nov. 2013
Java 8
2014
• Javaslang 1.0
• Mar. 2014
• AC 4.1
• Nov. 2015
• Eclipse Collections
7.0 (EC)
• Jan. 2016
• EC 8.0 (Java 8)
• Sept. 2016
• Guava 20.0
• Oct. 2016
• Javaslang 2.1a
• Nov. 2016
Java 9
2017
• Guava 21.0
(Java 8)
• Jan. 2017
• EC 8.1
• Mar. 2017
• Vavr 0.9
• May 2017
• Guava 22.0
• May 2017
• EC 8.2
• Jun 2017
• Guava 23.0
• Aug 2017
• EC 9.0
• Sep 2017

13. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Collections.compare();

14. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Use Case – Deck of Cards

15. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Problem Statement – Deck of Cards
1. Create Deck of Cards
• Store Cards in an “ImmutableList”
• (Cartesian product of Suit x Rank)
• Group the cards by Suit in an “ImmutableListMultimap”
• (Group By)
2. Get the number of cards
• Count By Suit returning “Multiset” or “Bag”
• Count By Rank returning “Multiset” or “Bag”
3. Deal five hands of five cards each
• Return the cards as an “ImmutableList” of five Sets of five cards

16. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Problem Statement – Deck of Cards
1. Create Deck of Cards
• Store Cards in an “ImmutableList”
• (Cartesian product of Suit x Rank)
• Group the cards by Suit in an “ImmutableListMultimap”
• (Group By)
2. Get the number of cards
• Count By Suit returning “Multiset” or “Bag”
• Count By Rank returning “Multiset” or “Bag”
3. Deal five hands of five cards each
• Return the cards as an “ImmutableList” of five Sets of five cards

17. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Performance Test - Deck of Cards
166,268
179,728
147,495
179,159
165,415
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
180,000
200,000
Scoreops/s
Framework
Deck of Cards
Apache EC Guava JDK Vavr

18. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Performance Notes
• JDK and Apache do not have Immutable
Collections
• Guava’s ImmutableList is backed by an
ImmutableList
• Eclipse Collection’s ImmutableList is backed
by an array
• JavaSlang’s TreeSet is backed by a
RedBlackTree

19. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class JDK8DeckOfCards {
private List<Card> cards;
private Map<Suit, List<Card>> cardsBySuit;
A Deck of Cards – Only the Types
public class ApacheCommonsDeckOfCards {
private List<Card> cards;
private MultiValuedMap<Suit, Card> cardsBySuit;
public class EclipseCollectionsDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public class GoogleGuavaDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public class VavrDeckOfCards {
private List<Card> cards;
private Map<Suit, ? extends List<Card>> cardsBySuit;

20. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class JDK8DeckOfCards {
private List<Card> cards;
private Map<Suit, List<Card>> cardsBySuit;
A Deck of Cards – Only the Types
public class ApacheCommonsDeckOfCards {
private List<Card> cards;
private MultiValuedMap<Suit, Card> cardsBySuit;
public class EclipseCollectionsDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public class GoogleGuavaDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public class VavrDeckOfCards {
private List<Card> cards;
private Map<Suit, ? extends List<Card>> cardsBySuit;

21. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class JDK8DeckOfCards {
private List<Card> cards;
private Map<Suit, List<Card>> cardsBySuit;
A Deck of Cards – Only the Types
public class ApacheCommonsDeckOfCards {
private List<Card> cards;
private MultiValuedMap<Suit, Card> cardsBySuit;
public class EclipseCollectionsDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public class GoogleGuavaDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public class VavrDeckOfCards {
private List<Card> cards;
private Map<Suit, ? extends List<Card>> cardsBySuit;

22. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class JDK8DeckOfCards {
private List<Card> cards;
private Map<Suit, List<Card>> cardsBySuit;
A Deck of Cards – Only the Types
public class ApacheCommonsDeckOfCards {
private List<Card> cards;
private MultiValuedMap<Suit, Card> cardsBySuit;
public class EclipseCollectionsDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public class GoogleGuavaDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public class VavrDeckOfCards {
private List<Card> cards;
private Map<Suit, ? extends List<Card>> cardsBySuit;

23. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class JDK8DeckOfCards {
private List<Card> cards;
private Map<Suit, List<Card>> cardsBySuit;
A Deck of Cards – Only the Types
public class ApacheCommonsDeckOfCards {
private List<Card> cards;
private MultiValuedMap<Suit, Card> cardsBySuit;
public class EclipseCollectionsDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public class GoogleGuavaDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public class VavrDeckOfCards {
private List<Card> cards;
private Map<Suit, ? extends List<Card>> cardsBySuit;

24. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class JDK8DeckOfCards {
private List<Card> cards;
private Map<Suit, List<Card>> cardsBySuit;
A Deck of Cards – Only the Types
public class ApacheCommonsDeckOfCards {
private List<Card> cards;
private MultiValuedMap<Suit, Card> cardsBySuit;
public class EclipseCollectionsDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public class GoogleGuavaDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public class VavrDeckOfCards {
private List<Card> cards;
private Map<Suit, ? extends List<Card>> cardsBySuit;

25. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Problem Statement – Deck of Cards
1. Create Deck of Cards
• Store Cards in an “ImmutableList”
• (Cartesian product of Suit x Rank)
• Group the cards by Suit in an “ImmutableListMultimap”
• (Group By)
2. Get the number of cards
• Count By Suit returning “Multiset” or “Bag”
• Count By Rank returning “Multiset” or “Bag”
3. Deal five hands of five cards each
• Return the cards as an “ImmutableList” of five Sets of five cards

26. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Shared Code – Cartesian Product
public static Stream<Card> streamCards() {
return Card.cartesianProduct(
EnumSet.allOf(Rank.class),
EnumSet.allOf(Suit.class),
Card::new);
}
private static <A, B, C> Stream<C> cartesianProduct(
Set<A> set1,
Set<B> set2,
Function2<A, B, C> function) {
return set1.stream().flatMap(first ->
set2.stream().map(second ->
function.apply(first, second)));
}

27. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Eclipse Collections – Cartesian Product
public static LazyIterable<Card> lazyCards()
{
return Sets.cartesianProduct(
EnumSet.allOf(Rank.class),
EnumSet.allOf(Suit.class),
Card::new);
}

28. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Performance Benchmarks
• JMH - Java Microbenchmark Harness
• http://openjdk.java.net/projects/code-tools/jmh/
• Measure Reported – Operations per
second
• Bigger numbers are better
• 4 Core Intel i7, 50 Warm-up iterations, 30 measurement
iterations, 3 forks

29. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Memory Tests
• ObjectSizeCalculator.getObjectSize()
• Internal class in Nashorn
• Java 8
• Smaller numbers are better
• We test the size of the data structures created in each
code example

30. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Performance Test – ImmutableList
207,258
225,904
187,521 190,509
180,838
0
50,000
100,000
150,000
200,000
250,000
Scoreops/s
Framework
ImmutableList
Apache EC Guava JDK Vavr

31. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Memory Test – ImmutableList
2888
2776 2776
2896
2824
2700
2720
2740
2760
2780
2800
2820
2840
2860
2880
2900
2920
Framework
Bytes
ImmutableList
Apache EC Guava JDK Vavr

32. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class JDK8DeckOfCards {
private List<Card> cards;
private Map<Suit, List<Card>> cardsBySuit;
public JDK8DeckOfCards() {
this.cards = Collections.unmodifiableList(
Card.streamCards().sorted().collect(Collectors.toList()));
this.cardsBySuit =
this.cards.stream().collect(Collectors.collectingAndThen(
Collectors.groupingBy(
Card::getSuit,
Collectors.mapping(Function.identity(),
Collectors.collectingAndThen(
Collectors.toList(),
Collections::unmodifiableList))),
Collections::unmodifiableMap));
}
JDK Collections – “ImmutableList”

33. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
this.cards =
Collections.unmodifiableList(
Card.streamCards()
.sorted()
.collect(Collectors.toList()));
JDK Collections – “ImmutableList”

34. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class ApacheCommonsDeckOfCards {
private List<Card> cards;
private MultiValuedMap<Suit, Card> cardsBySuit;
public ApacheCommonsDeckOfCards() {
this.cards = ListUtils.unmodifiableList(
Card.streamCards().sorted().collect(Collectors.toList()));
ListValuedMap<Suit, Card> cbs = MultiMapUtils.newListValuedHashMap();
this.cards.forEach(card -> cbs.put(card.getSuit(), card));
this.cardsBySuit = MultiMapUtils.unmodifiableMultiValuedMap(cbs);
}
Apache Collections – “ImmutableList”

35. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
this.cards =
ListUtils.unmodifiableList(
Card.streamCards()
.sorted()
.collect(Collectors.toList()));
Apache Collections – “ImmutableList”

36. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class EclipseCollectionsDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public EclipseCollectionsDeckOfCards() {
this.cards = Card.lazyCards().toSortedList().toImmutable();
this.cardsBySuit = this.cards.groupBy(Card::getSuit);
}
Eclipse Collections – ImmutableList

37. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
this.cards =
Card.lazyCards()
.toSortedList()
.toImmutable();
Eclipse Collections – ImmutableList

38. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class GoogleGuavaDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public GoogleGuavaDeckOfCards() {
this.cards =
Card.streamCards().sorted().collect(ImmutableList.toImmutableList());
this.cardsBySuit = Multimaps.index(this.cards, Card::getSuit);
}
Google Guava – ImmutableList

39. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
this.cards =
Card.streamCards()
.sorted()
.collect(ImmutableList.toImmutableList());
Google Guava – ImmutableList

40. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class VavrDeckOfCards {
private List<Card> cards;
private Map<Suit, ? extends List<Card>> cardsBySuit;
public VavrDeckOfCards() {
this.cards = Card.streamCards().sorted().collect(List.collector());
this.cardsBySuit = this.cards.groupBy(Card::getSuit);
}
Vavr – ImmutableList

41. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
this.cards =
Card.streamCards()
.sorted()
.collect(List.collector());
Vavr – ImmutableList

42. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Performance Notes
• Guava’s ImmutableList Collector uses an
ArrayBasedBuilder for adding elements
• The final build step creates the sorts the array and
constructs the ImmutableList
• Eclipse Collections creates a TreeSet from
the array of cards
• The TreeSet is converted to an array via toArray
for final storage

43. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Problem Statement – Deck of Cards
1. Create Deck of Cards
• Store Cards in an “ImmutableList”
• (Cartesian product of Suit x Rank)
• Group the cards by Suit in an “ImmutableListMultimap”
• (Group By)
2. Get the number of cards
• Count By Suit returning “Multiset” or “Bag”
• Count By Rank returning “Multiset” or “Bag”
3. Deal five hands of five cards each
• Return the cards as an “ImmutableList” of five Sets of five cards

44. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Performance Test - groupBy
832,841
617,693
459,074
1,123,706
695,402
-
200,000
400,000
600,000
800,000
1,000,000
1,200,000
Scoreops/s
Framework
groupBy
Apache EC Guava JDK Vavr

45. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Memory Test – groupBy
3336
2952
3136
3336
4208
0
500
1000
1500
2000
2500
3000
3500
4000
4500
Framework
Bytes
groupBy
Apache EC Guava JDK Vavr

46. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class JDK8DeckOfCards {
private List<Card> cards;
private Map<Suit, List<Card>> cardsBySuit;
public JDK8DeckOfCards() {
this.cards = Collections.unmodifiableList(
Card.streamCards().sorted().collect(Collectors.toList()));
this.cardsBySuit =
this.cards.stream().collect(Collectors.collectingAndThen(
Collectors.groupingBy(
Card::getSuit,
Collectors.mapping(Function.identity(),
Collectors.collectingAndThen(
Collectors.toList(),
Collections::unmodifiableList))),
Collections::unmodifiableMap));
}
JDK Collections – Group By

47. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
this.cardsBySuit =
this.cards.stream().collect(Collectors.collectingAndThen(
Collectors.groupingBy(
Card::getSuit,
Collectors.mapping(Function.identity(),
Collectors.collectingAndThen(
Collectors.toList(),
Collections::unmodifiableList))),
Collections::unmodifiableMap));
JDK Collections – Group By

48. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class ApacheCommonsDeckOfCards {
private List<Card> cards;
private MultiValuedMap<Suit, Card> cardsBySuit;
public ApacheCommonsDeckOfCards() {
this.cards = ListUtils.unmodifiableList(
Card.streamCards().sorted().collect(Collectors.toList()));
ListValuedMap<Suit, Card> cbs = MultiMapUtils.newListValuedHashMap();
this.cards.forEach(card -> cbs.put(card.getSuit(), card));
this.cardsBySuit = MultiMapUtils.unmodifiableMultiValuedMap(cbs);
}
Apache Collections – Group By

49. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
ListValuedMap<Suit, Card> cbs =
MultiMapUtils.newListValuedHashMap();
this.cards.forEach(
card -> cbs.put(card.getSuit(), card));
this.cardsBySuit =
MultiMapUtils.unmodifiableMultiValuedMap(cbs);
Apache Collections – Group By

50. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public class EclipseCollectionsDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public EclipseCollectionsDeckOfCards() {
this.cards = Card.lazyCards().toSortedList().toImmutable();
this.cardsBySuit = this.cards.groupBy(Card::getSuit);
}
Eclipse Collections – Group By

51. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
this.cardsBySuit =
this.cards.groupBy(Card::getSuit);
Eclipse Collections – Group By

52. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Google Guava – Group By
public class GoogleGuavaDeckOfCards {
private ImmutableList<Card> cards;
private ImmutableListMultimap<Suit, Card> cardsBySuit;
public GoogleGuavaDeckOfCards() {
this.cards =
Card.streamCards().sorted().collect(ImmutableList.toImmutableList());
this.cardsBySuit = Multimaps.index(this.cards, Card::getSuit);
}

53. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
this.cardsBySuit =
Multimaps.index(this.cards, Card::getSuit);
Google Guava – Group By

54. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Vavr – Group By
public class VavrDeckOfCards {
private List<Card> cards;
private Map<Suit, ? extends List<Card>> cardsBySuit;
public VavrDeckOfCards() {
this.cards = Card.streamCards().sorted().collect(List.collector());
this.cardsBySuit = this.cards.groupBy(Card::getSuit);
}

55. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
this.cardsBySuit =
this.cards.groupBy(Card::getSuit);
Vavr – Group By

56. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Performance Test - Deck of Cards
207,258
225,904
187,521 190,509 180,838
ImmutableList
832,841
617,693
459,074
1,123,706
695,402
groupBy
166,268
179,728
147,495
179,159
165,415
Deck of Cards
Apache EC Guava JDK Vavr

57. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Memory Test – Deck of Cards
3608
3216
3400
3720
5480
0
1000
2000
3000
4000
5000
6000
Framework
Bytes
Deck of Cards
Apache EC Guava JDK Vavr

58. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Problem Statement – Deck of Cards
1. Create Deck of Cards
• Store Cards in an “ImmutableList”
• (Cartesian product of Suit x Rank)
• Group the cards by Suit in an “ImmutableListMultimap”
• (Group By)
2. Get the number of cards
• Count By Suit returning “Multiset” or “Bag”
• Count By Rank returning “Multiset” or “Bag”
3. Deal five hands of five cards each
• Return the cards as an “ImmutableList” of five Sets of five cards

59. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Performance Test - countsBySuit
1,302,792
1,797,399
1,488,693
1,553,906
1,432,836
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000
1,400,000
1,600,000
1,800,000
2,000,000
Scoreops/s
Framework
countsBySuit
Apache EC Guava JDK Vavr

60. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Memory Test - countsBySuit
672
408
704
600 600
0
100
200
300
400
500
600
700
800
Framework
Bytes
countsBySuit
Apache EC Guava JDK Vavr

61. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Performance Test - countsByRank
889,401
1,339,267
1,136,795
1,289,520
1,208,456
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000
1,400,000
1,600,000
Scoreops/s
Framework
countsByRank
Apache EC Guava JDK Vavr

62. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Memory Test – countsByRank
1816
1136
1848
1600 1600
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Framework
Bytes
countsByRank
Apache EC Guava JDK Vavr

63. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public Map<Suit, Long> countsBySuit() {
return this.cards.stream()
.collect(Collectors.groupingBy(
Card::getSuit, Collectors.counting()));
}
public Map<Rank, Long> countsByRank() {
return this.cards.stream()
.collect(Collectors.groupingBy(
Card::getRank, Collectors.counting()));
}
JDK Collections – Count By

64. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public Bag<Suit> countsBySuit() {
return this.cards.stream()
.map(Card::getSuit)
.collect(Collectors.toCollection(HashBag::new));
}
public MultiSet<Rank> countsByRank() {
return this.cards.stream()
.map(Card::getRank)
.collect(Collectors.toCollection(HashMultiSet::new));
}
Apache Collections – Count By

65. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public Bag<Suit> countsBySuit() {
return this.cards.countBy(Card::getSuit);
}
public Bag<Rank> countsByRank() {
return this.cards.countBy(Card::getRank);
}
Eclipse Collections – Count By

66. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public Multiset<Suit> countsBySuit() {
return this.cards.stream()
.collect(Multisets.toMultiset(
Card::getSuit, e -> 1, HashMultiset::create));
}
public Multiset<Rank> countsByRank() {
return this.cards.stream()
.collect(Multisets.toMultiset(
Card::getRank, e -> 1, HashMultiset::create));
}
Google Guava – Count By

67. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
public java.util.Map<Suit, Long> countsBySuit() {
return this.cards.collect(
Collectors.groupingBy(
Card::getSuit,
Collectors.counting()));
}
public java.util.Map<Rank, Long> countsByRank() {
return this.cards.collect(
Collectors.groupingBy(
Card::getRank,
Collectors.counting()));
}
Vavr – Count By

68. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Problem Statement – Deck of Cards
1. Create Deck of Cards
• Store Cards in an “ImmutableList”
• (Cartesian product of Suit x Rank)
• Group the cards by Suit in an “ImmutableListMultimap”
• (Group By)
2. Get the number of cards
• Count By Suit returning “Multiset” or “Bag”
• Count By Rank returning “Multiset” or “Bag”
3. Deal five hands of five cards each
• Return the cards as an “ImmutableList” of five Sets of five cards

69. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Performance Test – Deal Hands
935,213
1,320,811
935,860 945,125
716,883
0
200,000
400,000
600,000
800,000
1,000,000
1,200,000
1,400,000
Scoreops/s
Framework
Deal
Apache EC Guava JDK Vavr

70. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Memory Test – Deal Hands
3528
2440
3488 3536
3120
0
500
1000
1500
2000
2500
3000
3500
4000
Framework
Bytes
Deal
Apache EC Guava JDK Vavr

71. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
JDK Collections – Deal Hands
public List<Set<Card>> dealHands(
Deque<Card> shuffled,
int hands,
int cardsPerHand)
{
return Collections.unmodifiableList(
IntStream.range(0, hands)
.mapToObj(i -> this.deal(shuffled, cardsPerHand))
.collect(Collectors.toList()));
}

72. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Apache Collections – Deal Hands
public List<Set<Card>> dealHands(
Deque<Card> shuffled,
int hands,
int cardsPerHand)
{
return ListUtils.unmodifiableList(
IntStream.range(0, hands)
.mapToObj(i -> this.deal(shuffled, cardsPerHand))
.collect(Collectors.toList()));
}

73. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Eclipse Collections – Deal Hands
public ImmutableList<Set<Card>> dealHands(
MutableStack<Card> shuffled,
int hands,
int cardsPerHand)
{
return IntInterval.oneTo(hands)
.collect(i -> this.deal(shuffled, cardsPerHand));
}

74. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Google Guava – Deal Hands
public ImmutableList<Set<Card>> dealHands(
Deque<Card> shuffled,
int hands,
int cardsPerHand)
{
return IntStream.range(0, hands)
.mapToObj(i -> this.deal(shuffled, cardsPerHand))
.collect(ImmutableList.toImmutableList());
}

75. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Vavr – Deal Hands
public List<Set<Card>> dealHands(
Stack<Card> shuffled,
int hands,
int cardsPerHand) {
List<Set<Card>> list = List.empty();
for (int i = 0; i < hands; i++) {
Tuple2<Set<Card>, ? extends Stack<Card>> tuple2 =
this.deal(shuffled, cardsPerHand);
shuffled = tuple2._2();
list = list.append(tuple2._1());
}
return list;
}

76. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Feature JDK Apache Guava Eclipse Vavr 1st, 2nd, 3rd
List, Set, Map ✔ þ ✖ ✔ þ JDK, EC, JS
Multiset / Bag ✖ ✔ ✔ ✔ ✖ GG, EC, AC
Multimap ✖ ✔ ✔ ✔ ✔ GG, EC, AC
BiMap ✖ ✔ ✔ ✔ ✖ GG, EC, AC
Stack ✔ þ ✖ ✔ ✔ EC, JDK, JS
Tree / Trie ✖ ✔ ✖ ✖ ✔ JS, AC
Table ✖ ✖ ✔ ✖ ✖ GG
Additional Types ✔ ✔ ✔ ý ý AC, JDK, GG
Immutable? ✖ ✖ ✔ ✔ ✔ JS, EC, GG
Primitives? ý ✖ ý ✔ ✖ EC, JDK, GG
Fluent API þ ý ý ✔ ✔ EC, JS, JDK
(E), (L), (S), (P)* ý, ✔, ✔, ✔ þ, þ, ✔, ✖ ✖, þ, ✔, ✖ ✔, ✔, ✔, ✔ ✔, ✔, ✔, ✖ EC, JDK, JS
Collection Framework Comparison
*(E)ager, (L)azy, (S)erial, (P)arallel – Functional API

77. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Links
— The Collections Compare Project
— https://github.com/nikhilnanivadekar/Coll
ectionsCompare

78. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
? & !

79. Collections.compare(()->{…})
@TheDonRaab @leomrlima @NikhilNanivade#JavaOne
Thanks!