JavaOne 2017 - Collections.compare:JDK, Eclipse, Guava, Apache... [CON1754]

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@TheDonRaab @leomrlima @NikhilNanivade#JavaOne

Collections.compare(() -> {JDK; Apache; Eclipse; Guava...});

Donald Raab

Leonardo Lima

Nikhil J. Nanivadekar

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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 opensource 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!

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Agenda1. 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)

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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

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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]

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�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

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java.util.Collections

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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

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Java 21998

• Interfaces• Collection• List• Set• Map• List• SortedMap

Java 52005

• Generics• For-each loop• Interfaces

• Iterable• Queue• ConcurrentMap• BlockingQueue

Java 62006

•Interfaces•NavigableSet•NavigableMap•Deque•BlockingDeque•ConcurrentNavigableMap

Java 72011

• Interfaces• TransferQueu

e

Java 82014

• 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

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!java.util.Collections?

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!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!)

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Collection Frameworks Timeline

Java 21998

• JakartaCollections 1.0• 2001

• Apache Collections 3.0 (AC)• 2004

Java 62006

• Google Collections 1.0• Dec. 2009

Java 72011

• Google Guava 10.0• Sept. 2011

• GS Collections 1.0• Jan. 2012

• AC 4.0• Nov. 2013

Java 82014

• 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 92017

• 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

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Collections.compare();

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Use Case – Deck of Cards

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Problem Statement – Deck of Cards1. 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

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Performance Test - Deck of Cards

166,268179,728

147,495

179,159165,415

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Deck of Cards

Apache EC Guava JDK Vavr

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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

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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;

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Shared Code – Cartesian Productpublic 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)));}

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Eclipse Collections – Cartesian Product

public static LazyIterable<Card> lazyCards() {

return Sets.cartesianProduct(EnumSet.allOf(Rank.class),EnumSet.allOf(Suit.class),Card::new);

}

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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

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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

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Performance Test – ImmutableList

207,258

225,904

187,521 190,509180,838

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Memory Test – ImmutableList

2888

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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”

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this.cards = Collections.unmodifiableList(

Card.streamCards().sorted().collect(Collectors.toList()));

JDK Collections – “ImmutableList”

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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”

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this.cards = ListUtils.unmodifiableList(

Card.streamCards().sorted().collect(Collectors.toList()));

Apache Collections – “ImmutableList”

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public EclipseCollectionsDeckOfCards() {this.cards = Card.lazyCards().toSortedList().toImmutable();this.cardsBySuit = this.cards.groupBy(Card::getSuit);

}

Eclipse Collections – ImmutableList

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this.cards = Card.lazyCards()

.toSortedList()

.toImmutable();

Eclipse Collections – ImmutableList

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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

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this.cards = Card.streamCards()

.sorted()

.collect(ImmutableList.toImmutableList());

Google Guava – ImmutableList

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public VavrDeckOfCards() {this.cards = Card.streamCards().sorted().collect(List.collector());this.cardsBySuit = this.cards.groupBy(Card::getSuit);

}

Vavr – ImmutableList

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this.cards = Card.streamCards()

.sorted()

.collect(List.collector());

Vavr – ImmutableList

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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

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Performance Test - groupBy

832,841

617,693

459,074

1,123,706

695,402

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Memory Test – groupBy

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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(),


Collections::unmodifiableMap));}

JDK Collections – Group By

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this.cardsBySuit =this.cards.stream().collect(Collectors.collectingAndThen(

Collectors.groupingBy(Card::getSuit,Collectors.mapping(Function.identity(),


Collections::unmodifiableMap));

JDK Collections – Group By

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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

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ListValuedMap<Suit, Card> cbs = MultiMapUtils.newListValuedHashMap();

this.cards.forEach(card -> cbs.put(card.getSuit(), card));

this.cardsBySuit = MultiMapUtils.unmodifiableMultiValuedMap(cbs);

Apache Collections – Group By

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public EclipseCollectionsDeckOfCards() {this.cards = Card.lazyCards().toSortedList().toImmutable();this.cardsBySuit = this.cards.groupBy(Card::getSuit);

}

Eclipse Collections – Group By

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this.cardsBySuit = this.cards.groupBy(Card::getSuit);

Eclipse Collections – Group By

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Google Guava – Group Bypublic 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);

}

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this.cardsBySuit = Multimaps.index(this.cards, Card::getSuit);

Google Guava – Group By

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Vavr – Group By


public VavrDeckOfCards() {this.cards = Card.streamCards().sorted().collect(List.collector());this.cardsBySuit = this.cards.groupBy(Card::getSuit);

}

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this.cardsBySuit = this.cards.groupBy(Card::getSuit);

Vavr – Group By

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Performance Test - Deck of Cards

207,258225,904

187,521 190,509 180,838

ImmutableList

832,841

617,693 459,074

1,123,706

695,402

groupBy

166,268179,728

147,495

179,159165,415

Deck of Cards


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Memory Test – Deck of Cards

36083216

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Performance Test - countsBySuit

1,302,792

1,797,399

1,488,6931,553,906

1,432,836

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Memory Test - countsBySuit

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Performance Test - countsByRank

889,401

1,339,267

1,136,795

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Memory Test – countsByRank

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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

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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

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public Bag<Suit> countsBySuit() {return this.cards.countBy(Card::getSuit);

}

public Bag<Rank> countsByRank() {return this.cards.countBy(Card::getRank);

}

Eclipse Collections – Count By

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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

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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

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Performance Test – Deal Hands

935,213

1,320,811

935,860 945,125

716,883

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Memory Test – Deal Hands

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JDK Collections – Deal Handspublic 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()));

}

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Apache Collections – Deal Handspublic 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()));

}

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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));}

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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());}

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Vavr – Deal Handspublic 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;

}

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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

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Links� The Collections Compare Project� https://github.com/nikhilnanivadekar/Coll

ectionsCompare

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? & !

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Thanks!

JavaOne 2017 - Collections.compare:JDK, Eclipse, Guava, Apache... [CON1754]

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